Confused by nitrates

[js-3Design]

A skimmer isn't going to help much at all with dissolved nutrient levels, regardless of tuning or maintenance routine, but I'm still curious why you have two skimmers? Would a single unit be preferred since it would take up less space and be a little more efficient than two?

Here's the thing...

Dissolved nutrient levels correspond to feeding levels.

Feeding levels are dictated by your quantity (mass) of livestock.

Your tank is overstocked by most conventional definitions.

As a result you are overfeeding the tank in comparison to what it can process (not necessarily related to tank size) – this is how dissolved nutrients happen.

You might ALSO be overfeeding beyond what your livestock needs OR things that are not being well-utilized...mandarin and coral feedings are notoriously bad on this, just for two examples.

FYI, "export" can only mop up after "the mess" has been made. To prevent problems (eg algae blooms, etc) you will want to prevent the mess from happening instead cleaning it up afterward.

And if you aren't having any problems (Ie. if you're just trying to change the numbers on the test kits) then be careful about any changes you make. "High nutrients" aren't a problem per se....plenty of killer reef tanks out there have nutrient levels that are crazy high compared to what's typically been preached in the hobby. It's helpful IMO to remember that nitrogen and phosphorus are essential major nutrients – not "waste" or "toxic" or whatever. The distinction will help with understanding when something does go wrong. For example, it's more likely to be a problem if you have "zero nutrients" than if you have "high nutrients".

Real reefs do not have "zero nutrient" water, and the only reason water tests show low numbers at some reefs is from the reef using and recycling up 99.9% of the available nutrients.....NOT because there are no nutrients...not even because the water is clean....almost the opposite....the reef is there because of the available nutrients, but it's such a perfectly efficient ecosystem that the water is the way it is once the reef is established. This "clean" water is a result of the reef, not a precondition for it.

IMO, make sure you aren't wasting food in the tank. Broadcast feeding wastes A LOT if you are doing that...switch to target feeding, incidental feeding or figure something else out. If you are sure you aren't wasting food, then consider reducing the amount of livestock in the tank.....personally I'd re-home the Tang since the tank is not the right size for it anyway, but reduce livestock mass somehow. Less livestock = less feeding = less dissolved nutrients.

I would discontinue things like carbon dosing if you're still doing any "extras" like that. Reduce nutrient inputs and the problem will resolve on its own (and respond better to your cleanup efforts).

well about the overstocking... No its not overstocked.

I run a 50g with 2 clowns, 7 chromis, 1, foxface, 1 sandsifter, 1 dottyback, 1 tailspot wrasse I feed 2 3 (washed) cubes frozen food a day and some nori.
And I'm dosing po4 and amonium because my nutrients bottom out otherwise....
offcourse every aquarium is different but to say op's aquarium is overstocked...

I do agree the high nitrates have a source, offcourse, but I've what op is saying about his feeding schedule is true I believe he should start with changing the socks and try to see if the skimmers are the source..

 

[SudzFD]

My bet is on the bio spheres.

Bio media can sometimes become nitrate factories.

I agree with this. In the AIO setup. Detritus becomes trapped below the bio balls and other areas in the back that are impossible to see. It would be a good idea to pull the bioballs place them in a bucket of tank water and clean out the chamber.

Also, a thought to share. Your nitrates will always be a problem without a refugium. They just are a product of your fish and water changes really are limited in their reduction ability.

A refugium does not have to be big.

If it was me, I’d ditch one of the protein skimmers and get a small led grow light that can go over that area (or if it’s clear back you can get a cheap Amazon one to shine in through the back glass. Put a ball of chaeto in there and maybe dose some occasional chaeto grow and watch your nitrates fall.

If you want to keep both skimmers you might be able to do something like this in the bio ball area. Don’t be afraid to remove some of those. Your bacteria filtration is far more established in your live rock (considering you have rock in the tank)

 

[bdub2583]

Keep us updated! Would like to know what it is lol so if anyone else runs into the issue lol

I will for sure!

 

[bdub2583]

A skimmer isn't going to help much at all with dissolved nutrient levels, regardless of tuning or maintenance routine, but I'm still curious why you have two skimmers? Would a single unit be preferred since it would take up less space and be a little more efficient than two?

Here's the thing...

Dissolved nutrient levels correspond to feeding levels.

Feeding levels are dictated by your quantity (mass) of livestock.

Your tank is overstocked by most conventional definitions.

As a result you are overfeeding the tank in comparison to what it can process (not necessarily related to tank size) – this is how dissolved nutrients happen.

You might ALSO be overfeeding beyond what your livestock needs OR things that are not being well-utilized...mandarin and coral feedings are notoriously bad on this, just for two examples.

FYI, "export" can only mop up after "the mess" has been made. To prevent problems (eg algae blooms, etc) you will want to prevent the mess from happening instead cleaning it up afterward.

And if you aren't having any problems (Ie. if you're just trying to change the numbers on the test kits) then be careful about any changes you make. "High nutrients" aren't a problem per se....plenty of killer reef tanks out there have nutrient levels that are crazy high compared to what's typically been preached in the hobby. It's helpful IMO to remember that nitrogen and phosphorus are essential major nutrients – not "waste" or "toxic" or whatever. The distinction will help with understanding when something does go wrong. For example, it's more likely to be a problem if you have "zero nutrients" than if you have "high nutrients".

Real reefs do not have "zero nutrient" water, and the only reason water tests show low numbers at some reefs is from the reef using and recycling up 99.9% of the available nutrients.....NOT because there are no nutrients...not even because the water is clean....almost the opposite....the reef is there because of the available nutrients, but it's such a perfectly efficient ecosystem that the water is the way it is once the reef is established. This "clean" water is a result of the reef, not a precondition for it.

IMO, make sure you aren't wasting food in the tank. Broadcast feeding wastes A LOT if you are doing that...switch to target feeding, incidental feeding or figure something else out. If you are sure you aren't wasting food, then consider reducing the amount of livestock in the tank.....personally I'd re-home the Tang since the tank is not the right size for it anyway, but reduce livestock mass somehow. Less livestock = less feeding = less dissolved nutrients.

I would discontinue things like carbon dosing if you're still doing any "extras" like that. Reduce nutrient inputs and the problem will resolve on its own (and respond better to your cleanup

I agree with this. In the AIO setup. Detritus becomes trapped below the bio balls and other areas in the back that are impossible to see. It would be a good idea to pull the bioballs place them in a bucket of tank water and clean out the chamber.

Also, a thought to share. Your nitrates will always be a problem without a refugium. They just are a product of your fish and water changes really are limited in their reduction ability.

A refugium does not have to be big.

If it was me, I’d ditch one of the protein skimmers and get a small led grow light that can go over that area (or if it’s clear back you can get a cheap Amazon one to shine in through the back glass. Put a ball of chaeto in there and maybe dose some occasional chaeto grow and watch your nitrates fall.

If you want to keep both skimmers you might be able to do something like this in the bio ball area. Don’t be afraid to remove some of those. Your bacteria filtration is far more established in your live rock (considering you have rock in the tank)

I have been exploring the refugium route, not sure that I want to run one in the rear chambers though. Not because I want to run dual skimmers but because it’s more difficult to maintain. I have been thinking of building a smaller 5-10 gallon external macro tank and plumb into the AIO section via pump and overflow.

 

[kboogie]

The cool thing is, we can do the math on this, and it might help with the explanation. If we assume each fish is consuming 2% of their body weight each day of average quality food then each goby and dragonet will produce about 1.8mg of ammonia per day, each clown fish produces 9.5mg of ammonia per day, and your tang produces about 63mg of ammonia per day. Based on the molar mass of ammonia and nitrate, we can multiply that by 4 to determine the amount of nitrate per day, which is 7.2mg, 38mg, and 252mg, respectively. So that means you are producing about 380mg of nitrate per day from just the fish. If there is 3.8L of water per gallon in a 47G aquarium, you have 178 liters divide your 380mg of nitrate by 178, and you get roughly 2ppm per day of nitrate just from the fish. That does not include any additional nitrate from organic material breaking down. If you protein skimmer exports 20% of that, you still have 1.6ppm of nitrate per day, building just from the fish. Over the course of a month, that is 48ppm of nitrates. 25% weekly water changes are only removing one week of build up from the fish and nothing from the breakdown of other organics.

This tells us you need to dramatically increase your nutrient export. If you want to leverage water changes as your primary form of nutrient export, then you need to increase the size of each water change to 33% or 50%. You can (or should) add macro algae to help with nutrient export, you can get a chaeto reactor that won't require any additional room in your sump, I built my own for $35 with a cheap media recator and a cheep LED light strip. You can also do an algae scrubber, which works really well and is easy to harvest.

The last option is you can do what I currently do and get a denitrator and have worry-free nitrate export.

I wanted to show you the math so you can better understand why water changes in your situation make it difficult to export enough nitrates to get to the levels you desire.

 

[kboogie]

Also, I would consider switching to Reef Diapers instead of filter socks. Reed Diapers are disposable, do a much better job of capturing fine particles, and you don't have to rinse them out, so no leftover organics to breakdown. I used them before I got a new sump with a fleece roller. I love my Reed Diapers; they kept me in the hobby because rinsing filter socks is a pain.

 

[CHSUB]

Quite the predicament. Imo, you are doing many things right and I think your fish load and feedings are not outrageous. Having a Mandy, however, does complicate things as I suggested in another thread. The necessity of providing enough food for a fish that grazes makes controlling nutrients difficult.

Regardless of the new belief that run away nutrients are not detrimental and Joe Blow’s Reef is nice with high nutrient levels, it is not natural and generally leads to problems. So fixing the problem is your best move. I would remove the bio media in the back chamber as a first move and clean any accumulated detritus.

I’m curious to know more about your system? Do you have a sand bed, how much rock, during WC do you blow the rocks to remove detritus, how much coral?
Also a few pictures…

 

[js-3Design]

The cool thing is, we can do the math on this, and it might help with the explanation. If we assume each fish is consuming 2% of their body weight each day of average quality food then each goby and dragonet will produce about 1.8mg of ammonia per day, each clown fish produces 9.5mg of ammonia per day, and your tang produces about 63mg of ammonia per day. Based on the molar mass of ammonia and nitrate, we can multiply that by 4 to determine the amount of nitrate per day, which is 7.2mg, 38mg, and 252mg, respectively. So that means you are producing about 380mg of nitrate per day from just the fish. If there is 3.8L of water per gallon in a 47G aquarium, you have 178 liters divide your 380mg of nitrate by 178, and you get roughly 2ppm per day of nitrate just from the fish. That does not include any additional nitrate from organic material breaking down. If you protein skimmer exports 20% of that, you still have 1.6ppm of nitrate per day, building just from the fish. Over the course of a month, that is 48ppm of nitrates. 25% weekly water changes are only removing one week of build up from the fish and nothing from the breakdown of other organics.

This tells us you need to dramatically increase your nutrient export. If you want to leverage water changes as your primary form of nutrient export, then you need to increase the size of each water change to 33% or 50%. You can (or should) add macro algae to help with nutrient export, you can get a chaeto reactor that won't require any additional room in your sump, I built my own for $35 with a cheap media recator and a cheep LED light strip. You can also do an algae scrubber, which works really well and is easy to harvest.

The last option is you can do what I currently do and get a denitrator and have worry-free nitrate export.

I wanted to show you the math so you can better understand why water changes in your situation make it difficult to export enough nitrates to get to the levels you desire.

thats a nice calculation. BUT you dont account for anything that consumes nitrates like corals, algeas, bacteria etc.
with your calculations my nitrate should be thru the roof. which they aren't.. I add nitrates and phosphates to the water i'm doing the water change with to not lower nutrients in the aquarium...

 

[kboogie]

The cool thing is, we can do the math on this, and it might help with the explanation. If we assume each fish is consuming 2% of their body weight each day of average quality food then each goby and dragonet will produce about 1.8mg of ammonia per day, each clown fish produces 9.5mg of ammonia per day, and your tang produces about 63mg of ammonia per day. Based on the molar mass of ammonia and nitrate, we can multiply that by 4 to determine the amount of nitrate per day, which is 7.2mg, 38mg, and 252mg, respectively. So that means you are producing about 380mg of nitrate per day from just the fish. If there is 3.8L of water per gallon in a 47G aquarium, you have 178 liters divide your 380mg of nitrate by 178, and you get roughly 2ppm per day of nitrate just from the fish. That does not include any additional nitrate from organic material breaking down. If you protein skimmer exports 20% of that, you still have 1.6ppm of nitrate per day, building just from the fish. Over the course of a month, that is 48ppm of nitrates. 25% weekly water changes are only removing one week of build up from the fish and nothing from the breakdown of other organics.

This tells us you need to dramatically increase your nutrient export. If you want to leverage water changes as your primary form of nutrient export, then you need to increase the size of each water change to 33% or 50%. You can (or should) add macro algae to help with nutrient export, you can get a chaeto reactor that won't require any additional room in your sump, I built my own for $35 with a cheap media recator and a cheep LED light strip. You can also do an algae scrubber, which works really well and is easy to harvest.

The last option is you can do what I currently do and get a denitrator and have worry-free nitrate export.

I wanted to show you the math so you can better understand why water changes in your situation make it difficult to export enough nitrates to get to the levels you desire.

thats a nice calculation. BUT you dont account for anything that consumes nitrates like corals, algeas, bacteria etc.
with your calculations my nitrate should be thru the roof. which they aren't.. I add nitrates and phosphates to the water i'm doing the water change with to not lower nutrients in the aquarium...

I’m sorry you interpreted the information I provided in that manner.

In the context of the issue, the information provided was to help understand the sourcing of nitrates and the level of nutrient export needed given the level of consumption from the current stock of coral.

It is valuable for people to understand the science and math behind nitrate production.

 

[bdub2583]

Quite the predicament. Imo, you are doing many things right and I think your fish load and feedings are not outrageous. Having a Mandy, however, does complicate things as I suggested in another thread. The necessity of providing enough food for a fish that grazes makes controlling nutrients difficult.

Regardless of the new belief that run away nutrients are not detrimental and Joe Blow’s Reef is nice with high nutrient levels, it is not natural and generally leads to problems. So fixing the problem is your best move. I would remove the bio media in the back chamber as a first move and clean any accumulated detritus.

I’m curious to know more about your system? Do you have a sand bed, how much rock, during WC do you blow the rocks to remove detritus, how much coral?
Also a few pictures…

Yes I do have a sand bed, roughly 50lbs of rock probably more on the higher side. Yes I do blow the rocks out with a blaster during water changes. Toadstool, 1 frogspawn 4 zoa frags of 10iish heads each, small colony of birds nest, multiple mushrooms, 3 rock nems, 1 bubble tip, 1 torch 2-3 heads, 1 Duncan 2 heads, acan with about 10+ heads, millepora that’s 4-5inch on each branch. I think that’s it I pulled my bio media out tonight during water change so I’ll monitor my nutrients and see where things go. I am waiting on filter cups to run floss instead of socks.

 

[bdub2583]

I’m sorry you interpreted the information I provided in that manner.

In the context of the issue, the information provided was to help understand the sourcing of nitrates and the level of nutrient export needed given the level of consumption from the current stock of coral.

It is valuable for people to understand the science and math behind nitrate production.

I appreciate your reply, I am a numbers kind of guy and that breaks it down for me to understand the physical breakdown of the ammonia cycle.

 

[bdub2583]

Yesterday NO3 was 133ppm, just did a small 15% water change as a test mainly to pull marine pure out of return chamber and siphon the chamber out. Removed skimmers and gave a thorough cleaning and put back in. I did this to test one thing at a time. Left marine pure out and filled back up. Let run for an hour and now my new base NO3 reading is 104ppm.I will continue my carbon dosing as normal with .6ml per day and 4.5ml of neophos. I’ll test NO3 again in a few days and update everyone. Hopefully I get to the source of this and help someone else out in the future.

 

[Idech]

How old is the tank ? You have a deep sand bed and with time, those harbor bacteria that die when in contact with water, thus producing ammonia.

If you have a lot of snails and fish that dig around, they might be constantly releasing those bacteria. It’s not enough to cause an ammonia spike, but enough to keep nitrates rising.

If that’s the case, getting (very cautiously) rid of part of the sand would help.

Just a thought.

 

[TeeJay87]

Quoted wrong person; post deleted

 

[mcarroll]

well about the overstocking... No its not overstocked.

I run a 50g with 2 clowns, 7 chromis, 1, foxface, 1 sandsifter, 1 dottyback, 1 tailspot wrasse I feed 2 3 (washed) cubes frozen food a day and some nori.
And I'm dosing po4 and amonium because my nutrients bottom out otherwise....
offcourse every aquarium is different but to say op's aquarium is overstocked...

Not here to argue academics like what overstocked means....your tank is even more overstocked. I'm glad you're making it work though. FYI your situation doesn't seem similar to what the OP is posting.

You can look up what overstocked means in academic sources (e.g. SRAC articles), BTW.

I appreciate your reply, I am a numbers kind of guy and that breaks it down for me to understand the physical breakdown of the ammonia cycle.

Numbers are good because they are some of the best clues. :)

The ever-increasing NO3 is undoubtedly from your food inputs, which are more than the tank can handle. Specifically, inputs are outpacing denitrification.

Unlike js's tank, which seems OK with it...an important distinction. Significant nitrogen inputs aren't coming from any other source...yes corals can fix some dissolved N2, for example, but that's minuscule in comparison to what you're adding in terms of food, and it's not going to show up in NO3 tests. Don't ignore the numbers – food is the root source of NO3.

You don't claim to have very low PO4, just unexplained NO3 buildup. The main thing to keep in mind is that it's not a real problem yet, unless your tank is having some side effects from it such as unwanted algae growth.

Have you tested your fresh water change water for NO3? Rule that out.

If you're running any filtration/additives that mess with N consumption (eg carbon dosing, any/all derivatives, extra filtration, "nitrate blocks", etc) consider discontinuing that (at least) while things get balanced.

If you haven't eliminated the possibility of bad flow/detritus buildup in the sand and gear as some have suggested, of course do that....cleaner/better obviously isn't going to hurt anything.

Check your sand under pumps and around rock work by purposefully stirring it up, either with a water jet from a pump, or with an instrument like a stick or your finger. If you get anything up in the water that's tan or darker, you may have a detritus/flow problem. It's useful to realize you can have a lot of flow (in terms of total GPH or number of pumps) and have bad flow. Yours might be fine, but consider it.

Things like filter socks can be help or harm....they should be cleaned as soon as they are notably dirty vs on a schedule....which can leave them running dirty. Better to run NO socks than leave them dirty for any time.

You mentioned the tank is young, 2 years old. Was is started with live or dead rock? Did you use any particular method to start it up? Any issues during start up or in Year 1?

Yesterday NO3 was 133ppm, just did a small 15% water change as a test mainly to pull marine pure out of return chamber and siphon the chamber out. Removed skimmers and gave a thorough cleaning and put back in. I did this to test one thing at a time. Left marine pure out and filled back up. Let run for an hour and now my new base NO3 reading is 104ppm.I will continue my carbon dosing as normal with .6ml per day and 4.5ml of neophos. I’ll test NO3 again in a few days and update everyone. Hopefully I get to the source of this and help someone else out in the future.

Good...I would remove all "extra" filtration as mentioned....the system obviously doesn't need anything "rushing" the cycle of N into NO3. :)

Also, IMO, discontinue carbon dosing...it's unlikely to help (has it so far?) and it's fairly likely (eventually) to drive a cyano bloom.

You did not claim low PO4 in the opening post, but this post suggests the system actually is PO4-starved.

In that case, this imbalance is the problem...bacteria (noticeably, denitrifiers, in your tank's case) are po4 starved, like the rest of the ecosystem. N-uptake is probably being suppressed across the whole reef ecosystem. Carbon dosing is going to exacerbate this condition in the tank.

Again, remove all excess filtration other than the skimmer. But with this PO4-deficit in mind and the "extras" out of the way, you can hit the problem head on....dose more PO4 until there is a stable 0.10 ppm in your tests. Maintain this 0.10 ppm level just like you would with alk – daily testing and dosing until you hit the target and have the dosing routine locked in...eventually weekly dosing or no dosing once things are re-balanced.

Recall: Your food inputs are BY FAR the dictating force on NO3 and PO4, and if you're feeding frozen as indicated, that should have a nice N:P balance.....so "prevailing winds" are in your favor here.

Hope this helps!

 

[bdub2583]

Not here to argue academics like what overstocked means....your tank is even more overstocked. I'm glad you're making it work though. FYI your situation doesn't seem similar to what the OP is posting.

You can look up what overstocked means in academic sources (e.g. SRAC articles), BTW.


Numbers are good because they are some of the best clues. :)

The ever-increasing NO3 is undoubtedly from your food inputs, which are more than the tank can handle. Specifically, inputs are outpacing denitrification.

Unlike js's tank, which seems OK with it...an important distinction. Significant nitrogen inputs aren't coming from any other source...yes corals can fix some dissolved N2, for example, but that's minuscule in comparison to what you're adding in terms of food, and it's not going to show up in NO3 tests. Don't ignore the numbers – food is the root source of NO3.

You don't claim to have very low PO4, just unexplained NO3 buildup. The main thing to keep in mind is that it's not a real problem yet, unless your tank is having some side effects from it such as unwanted algae growth.

Have you tested your fresh water change water for NO3? Rule that out.

If you're running any filtration/additives that mess with N consumption (eg carbon dosing, any/all derivatives, extra filtration, "nitrate blocks", etc) consider discontinuing that (at least) while things get balanced.

If you haven't eliminated the possibility of bad flow/detritus buildup in the sand and gear as some have suggested, of course do that....cleaner/better obviously isn't going to hurt anything.

Check your sand under pumps and around rock work by purposefully stirring it up, either with a water jet from a pump, or with an instrument like a stick or your finger. If you get anything up in the water that's tan or darker, you may have a detritus/flow problem. It's useful to realize you can have a lot of flow (in terms of total GPH or number of pumps) and have bad flow. Yours might be fine, but consider it.

Things like filter socks can be help or harm....they should be cleaned as soon as they are notably dirty vs on a schedule....which can leave them running dirty. Better to run NO socks than leave them dirty for any time.

You mentioned the tank is young, 2 years old. Was is started with live or dead rock? Did you use any particular method to start it up? Any issues during start up or in Year 1?



Good...I would remove all "extra" filtration as mentioned....the system obviously doesn't need anything "rushing" the cycle of N into NO3. :)

Also, IMO, discontinue carbon dosing...it's unlikely to help (has it so far?) and it's fairly likely (eventually) to drive a cyano bloom.

You did not claim low PO4 in the opening post, but this post suggests the system actually is PO4-starved.

In that case, this imbalance is the problem...bacteria (noticeably, denitrifiers, in your tank's case) are po4 starved, like the rest of the ecosystem. N-uptake is probably being suppressed across the whole reef ecosystem. Carbon dosing is going to exacerbate this condition in the tank.

Again, remove all excess filtration other than the skimmer. But with this PO4-deficit in mind and the "extras" out of the way, you can hit the problem head on....dose more PO4 until there is a stable 0.10 ppm in your tests. Maintain this 0.10 ppm level just like you would with alk – daily testing and dosing until you hit the target and have the dosing routine locked in...eventually weekly dosing or no dosing once things are re-balanced.

Recall: Your food inputs are BY FAR the dictating force on NO3 and PO4, and if you're feeding frozen as indicated, that should have a nice N:P balance.....so "prevailing winds" are in your favor here.

Hope this helps!

I have tested my source water, rodi is 0ppm NO3, after salt mix I am getting 0.5-0.8ppm, I don’t believe that would be much of a contributor.

Tank was a emergency tank transfer as the old tank began leaking. So it was new Carib sea special grade sand, 20-30lbs of live rock that has been in several systems previously, and 20-30 pounds of dry rock. I used microbactor 7 dosing. Tank did have lots of issues in first year, cyano, Dino’s, and the big one was an ich outbreak. During the fish less process the tank got a severe cyano bloom that lasted several months. During those several months it was only two fish and a minimal clean up crew. My neighbor needed to rehome some clowns so I put them through a qt process and put them in mid July. Then tang end of July. Mandarin was just introduced. There was still some cyano present when the clown were transferred from qt. I used manual removal and carbon dosing to beat it.

Every tank I have ever run tends to run a higher NO3 and low to very low PO4 typically have to dose either Neophos or make my own with trisodium phosphate. This is even without carbon dosing. You think the carbon dosing and holding PO4 at 0.04-0.05 is causing the lack of NO3 to N2 conversion? I have always been under the impression that as long as PO4 was available the NO3 up take would be present. So just so I know I’m understanding correctly, you suggest stop carbon dosing and holding PO4 at 0.1 and see where that leads? Or are you suggesting to continue carbon and elevate PO4 to 0.1?

The confusing part is that this tank before the ich outbreak had at least 6 more fish in it and no3 would routinely be staying at 15-20ppm. Just doesn’t make sense now with less bioload. I’m not overly concerned since all the corals are happy and VERY color but I don’t feel comfortable maintaining this high long term.

With the sand I do have a lot of nasarius snails as well as try to vacuum a small section during water changes. There typically is always debris that gets removed.

 

[mcarroll]

I have tested my source water, rodi is 0ppm NO3, after salt mix I am getting 0.5-0.8ppm, I don’t believe that would be much of a contributor.

Eliminating that is a good start!

Old rock can be great, but it's also a roll of the dice depending on the history of that rock. It's too soon to say for sure, but that could be the root of these issues.

Tank was a emergency tank transfer as the old tank began leaking. So it was new Carib sea special grade sand, 20-30lbs of live rock that has been in several systems previously, and 20-30 pounds of dry rock. I used microbactor 7 dosing.

Dead sand and dead rock are extra work to start with. I know it's "normal" but you just started these up like they were bio-balls in a wet-dry filter. There's nothing reefy about that...basically like a monoculture crop of bacteria, not diverse enough to make any kind of stability in the system. This has ramifications...

Tank did have lots of issues in first year, cyano, Dino’s, and the big one was an ich outbreak.

This is pretty common when starting with dead rock. This instability also makes fish disease statistically more likely to happen and likely to be more severe if/when it happens.

During the fish less process the tank got a severe cyano bloom that lasted several months. During those several months it was only two fish and a minimal clean up crew.

...a dubious process all the way around. Dr Tim says it's unnecessary right on his website, but you don't hear that repeated much. Traditional methods are better. Following the product directions is better. The problem is that bad info circulates heavily online (right along with the good!) and the hobby seems to get more and more trendy and less and less literate. Almost nobody new to the hobby starts a tank with the help of an expert anymore, not even a good book....if that kind of startup was rare before, it's unheard of now since the intarwebs is everyone's expert. ("What you readin' for?" --Bill Hicks)

My neighbor needed to rehome some clowns so I put them through a qt process and put them in mid July. Then tang end of July. Mandarin was just introduced. There was still some cyano present when the clown were transferred from qt. I used manual removal and carbon dosing to beat it.

Glad it worked out – IMO cyano can be one of the toughest to beat, even your solution doesn't work in lots of cases. Thankfully it often ends up dissipating on its own if you can find the cause – just never soon enough. Adding the fish that quickly and from dubious sources does carry some risk....ideally you'd have done that phase of the tank a little more conservatively. (But I get you were helping someone out too...sometimes it's worth the risk, but not always.)

Every tank I have ever run tends to run a higher NO3 and low to very low PO4 typically have to dose either Neophos or make my own with trisodium phosphate. This is even without carbon dosing.

This is worth more consideration because PO4 deprivation is a guaranteed ticket to reefing-heck.

Figure out how you can change your methods so this doesn't happen. (Carbon dosing and dead rock seem to be common elements in tanks that suffer this way, but there are lots of potential causes.)

You think the carbon dosing and holding PO4 at 0.04-0.05 is causing the lack of NO3 to N2 conversion? I have always been under the impression that as long as PO4 was available the NO3 up take would be present.

If you're having to dose up to 0.04 ppm, then presumably that's as high as PO4 levels get. Also, presumably the number drops, maybe to 0.00 ppm, between doses. (It only has to drop low enough to become unavailable...which is relative to the life in the tank. Of course 0.00 is "unavailable" to everything. :) )

So just so I know I’m understanding correctly, you suggest stop carbon dosing and holding PO4 at 0.1 and see where that leads? Or are you suggesting to continue carbon and elevate PO4 to 0.1?

Yes. Eliminate any filtration or other "extras" including carbon dosing and with the exception of protein skimming.

Dose up to 0.10 ppm PO4 and hold it there until things normalize (eg N and P are balanced, etc) and dosing isn't needed to keep PO4 from bottoming out. This guarantees availability to everything, even critters with weak uptake. IMO PO4-availability is crucial until the tank has completely matured.

In fact, the first time you dose up to 0.10, wait an hour and re-test. Find out how much short-term consumption there is – and re-dose to your target ppm if needed. Sometimes there is a huge "spike" in demand from the deprived state that can take levels back to unavailable levels in a hurry. But not always. Interesting to find out in any case.

The confusing part is that this tank before the ich outbreak had at least 6 more fish in it and no3 would routinely be staying at 15-20ppm. Just doesn’t make sense now with less bioload. I’m not overly concerned since all the corals are happy and VERY color but I don’t feel comfortable maintaining this high long term.

Plenty of things have happened that could have tweaked the whole systems' N & P uptake, and once things get out of balance there can be a cascade of problems. Luckily it sounds like you've already got most of those behind you!!

With the sand I do have a lot of nasarius snails as well as try to vacuum a small section during water changes. There typically is always debris that gets removed.

If there's always "dirt" or "debris" coming out of the sand during cleaning, that's an indicator that flow could be improved. Ideally food and even detritus is kept flowing around the tank until some critter (even coral) can eat it....corals eat slowly, so they need time....it takes good strong flow to keep these particles from getting dragged into the rocks or sand by gravity. My rule of thumb is to have strong enough flow that small sand grains should be tumbled by it. If it can't do that, it can't handle food or detritus either. (Your sand may not have particles small enough to judge this by....using flake food is another way to see your flow.....time how long it takes for 50% of the food to disappear from view. How long for 75%?? 100%. Improve your flow and increase those timeframes. This can mean you need more GPH, but it could also mean you need to rearrange the flow you have. Or both.