Balancing fish stocking for water parameters

[Indytraveler83]

I have a bit of an unusual problem, and I'm hoping I can get some suggestions on how to move forward from here:

I have a 90 gallon system with mostly soft coral, lps and anemones. I've bought and grown out some rather large colonies, including a leather coral that's nearing the size of a basketball, a zoa colony that's likely in excess of of 400 or so polyps and GSP that's grown about a foot across. I love the look of the soft corals and nem's in the system, and the overall goal is to have a system that the coral pretty much covers all the live rock.

My mistake however, may have been in stocking fish. I don't generally like the look of large fish in a smaller system, so I've gone mostly with smaller wrasse, anthias, etc. Almost all the fish in the system are nearly full grown, and the ones that aren't will take years to reach their full size (such as the baby marine betta). Despite having around 20 small fish in the system, nitrate gets consumed far faster than it is produced. I've been dosing nitrate, but even dosing around 1 ppm twice daily does little to keep nitrate readings up.

I've tried running the refugium lights for less time, turning off the skimmer and even cut the macroalgae in the refugium down quite a bit. All that seems to do is send phosphate levels through the roof, and does little to affect nitrate. (Tested with both API and red sea kits from two sources. The only time nitrate is even mildly readable is right after dosing).

I don't want to do anything drastic, as nitrate is the only thing that's not dead stable on a regular basis. I can keep calcium and alk levels in ideal range with weekly dosing, and all the other water parameters don't flinch. But... I also see corals suffer and close up if I don't heavily dose nitrate regularly, and my dosing levels keep elevating as these colonies rapidly grow. I'm also not able to do water changes as much as I'd like, because even a 10 gallon water change bottoms out nitrates and closes coral for days.

What, if anything, can I do to naturally push nitrate levels up in the system so that I can keep encouraging coral growth? Again, I can keep phosphate under control with my current filtration methods, but if I pull back, phosphate shoots up rapidly. (Usually levels are a bit high at .3-.5 ppm, but turning down the fuge lights or turning off the skimmer will send it to 1-2 ppm within days).

I was thinking of trying to add 1 fish that produces a ton a waste to the system, but a bit nervous as my system is already pretty full of fish. (Many of you would consider it overstocked already). I don't mind dosing nitrate, but the levels yo-yo up and down with dosing, and would like to see nitrate become a more stable value more naturally.

Basics on the system: 90 gallon with 30 gallon sump (120 gallon total volume) - large refugium, skimmer and filter socks used for filtration in the sump. Alk around 9 dkh, salinity 1.026, phosphate .3-.5 ppm, calcium 420, 0 ammonia, 0 nitrite. Temp 77-79. Again, the only one of the values that even flinches is nitrate, which is only readable at around .5 ppm 30 minutes after dosing, then drops to unreadable within a few hours.

 

[Mastiffsrule]

Evening,

Sounds like you have a really thriving tank. I am a going to call in @Peace River for back up on this. I have not run into this in a while. If I can remember correctly you are sort of in a cycle of feeding the No3 , having the growth, growth requiring more No3.

What I mean by this. Coral and bacteria are using the No3 to grow. By dosing the No3 you are promoting the bacteria and coral growth which in turn requires more no3. I would guess everything else is stable since you are only importing the No3. It disappears quickly as it is being used that fast.

I would not recommend adding fish. Then you are adding more food which will add Po4 on top of more No3. I suggest heading the opposite way. Need to slow down all the growth to get the nitrate usage to flatten out.

I am not sure exactly what your dosing routine is right now. If you have been increasing I would try to slow down on the amount you are increasing, or spread out the time between dosing. Do it slowly though, it will take time. Keep an eye on coral. Your goal is to get the corals to slow their growth , but over time. Just like any change

Now we will wait for an expert opinion and see if I remember correctly

 

[Peace River]

In addition to what @Mastiffsrule has already mentioned, have you considered a GFO reactor or Phosban to bring down the phosphate? Let's see if we can get some additional input...

#reefsquad

 

[saltyhog]

The elevated PO4 is also having a role in depressing your nitrate. I have the opposite problem. Since you have an LPS/softie tank and it appears to be thriving, why not just continue to dose nitrate (a dosing pump and a simple timer will make it easy and you can dose several times a day for stability.

The other option would be to do as @Peace River said and run GFO. Just go slowly and be careful not to lower it too much or too fast. I wouldn't try to get it much if any below 0.1. As you lower PO4 the NO3 should come up a little. I would monitor both PO4 and Nitrate very closely while doing this. If you bottom out PO4 and NO3, bad things could happen, not the least of which would be a dino bloom.

I highly recommend the Hanna ULR phosphate checker and NYOS, Salifert, Red Sea for nitrate.

 

[Indytraveler83]

The elevated PO4 is also having a role in depressing your nitrate.


If you bottom out PO4 and NO3, bad things could happen, not the least of which would be a dino bloom.

Can you expand on the first statement? Curious on the link/reason why elevated PO4 would suppress NO3.

I'm scared to death to use a reactor. While I know many have used them with success, I also see horror stories of them stripping a tank bare of nutrients and I've accidentally bottomed out PO4 through water changes with disasterous results.

Would holding nitrate dosing stable, reducing broadcast feeding and doing more regular water changes, while target feeding coral maybe help balance things? Or am I still on the wrong track?

 

[Indytraveler83]

What I mean by this. Coral and bacteria are using the No3 to grow. By dosing the No3 you are promoting the bacteria and coral growth which in turn requires more no3. I would guess everything else is stable since you are only importing the No3. It disappears quickly as it is being used that fast.

Hmm... I've thought on this statement for a little while. I always assumed that only coral and algae were consuming NO3. As my nuisance algae is minimal, I figured my only significant consumers of NO3 were coral and the macroalgae in the 'fuge.

So I take it that there's bacteria also consuming NO3? Total factor I did not consider. These ecosystems are complicated things!

 

[Indytraveler83]

In addition to what @Mastiffsrule has already mentioned, have you considered a GFO reactor or Phosban to bring down the phosphate? Let's see if we can get some additional input...

#reefsquad

As I said previously, the reactor scares me. I'm terrified of nuking the entire tank with a reactor. Would Phosban or even just running carbon (I don't use any in my system at all), be a less aggressive approach to help bring phosphate down?

 

[saltyhog]

Carbon wont do anything to the PO4 or NO3.

A reactor allows for more control IME. Just start out with a small amount and monitor every day.

 

[SPR1968]

It might be worth posting a tank picture so we can see the stocking levels and room available because the easiest way to solve your problem is to add more fish.

One persons definition of overstocking is different to another’s and in my case I like fish so.....

The other thing is, if youve created a super effective refugium with a massive demand for nutrients it will be constantly trying to use up what’s available, and as already mentioned I think, there are also bacteria colonising any rocks etc trying to do this for you as well.

I guess the bottom line is, if the tank is running well, your generally happy with it, and all you having to do add is nitrate, then why risk unsettling things ? You can do that with a doser as already said, and its just the opposite of someone dosing Nopox with a doser to get nitrates down.

Im a big advocate of GFO and I use loads of rowaphos in my systems, but maybe as your running a refugium which seems very effective, I probably wouldn’t add this at the moment unless you can no longer control the levels. I target around 0.03 or less.

 

[Indytraveler83]

It might be worth posting a tank picture so we can see the stocking levels and room available because the easiest way to solve your problem is to add more fish.

One persons definition of overstocking is different to another’s and in my case I like fish so.....

The other thing is, if youve created a super effective refugium with a massive demand for nutrients it will be constantly trying to use up what’s available, and as already mentioned I think, there are also bacteria colonising any rocks etc trying to do this for you as well.

I guess the bottom line is, if the tank is running well, your generally happy with it, and all you having to do add is nitrate, then why risk unsettling things ? You can do that with a doser as already said, and its just the opposite of someone dosing Nopox with a doser to get nitrates down.

Im a big advocate of GFO and I use loads of rowaphos in my systems, but maybe as your running a refugium which seems very effective, I probably wouldn’t add this at the moment unless you can no longer control the levels. I target around 0.03 or less.

Here's a full tank shot (please excuse the messy glass):

I would say this shot is a good representation of how crowded or not the system is. The fish all expect food so they are out in the water column a bit more than usual.

Again, my biggest goal isn't to chase numbers or anything like that. It's simply to keep nitrate from bottoming out and stressing/killing corals. I just lost several monti frags to a nitrate drop, and I'm just trying to prevent that.

As was alluded to by @Mastiffsrule , my nitrate demand keeps increasing, as does my dosing, leading to a rise and fall that detracts from the stability I seek.

 

[Mastiffsrule]

Hello,

Tank looks great, leather is awesome. I think right there is the major nutrient guzzler. Sorry if I missed. i Saw number for stability. What are you dosing or using to keep stable all the other #’s. (How are you keeping calcium,alk,mag all those stable)

 

[Ettore]

All I wanted to say here is I called innovative marine customer service and they are truly the best Best customer service I’ve ever had for a marine company

 

[Indytraveler83]

Hello,

Tank looks great, leather is awesome. I think right there is the major nutrient guzzler. Sorry if I missed. i Saw number for stability. What are you dosing or using to keep stable all the other #’s. (How are you keeping calcium,alk,mag all those stable)

Agreed about the leather. It was a sizable 8 year old leather that was traded in to a local lfs because it's poor owner had grown too old to care for his tank. It's about doubled in size since I got it just a few months ago.

Source water (nope, I don't use RODI) is already very high in calcium, mag and alk, so top offs help restore much of that. So I just use Seachem Reef Fusion. Part 2 is weekly, part 1 is maybe every two weeks depending on calcium uptake.

 

[Mastiffsrule]

Did you have the No3 issue before the leather

 

[Indytraveler83]

Did you have the No3 issue before the leather

Now that I'm thinking about it... not as bad. I could previously keep it around 5 ppm with only dosing about 2x a week. The first month I had the leather it didn't really change, but as it's exploded in size, the problem has gotten much worse.

So if the leather is the reason... What's the best approach to stabilizing without removing it? Keep up the high dosing? Add livestock? Something else?

 

[SPR1968]

The tank looks very nice and doesn’t look anywhere near over stocked in my eyes and I love that leather coral, no way would I get rid of that. Although if I was a little closer I might recommend you do and give it to me! Lol

I guess you have several options including more fish, dosing nitrate etc so it’s a personal choice.

 

[Indytraveler83]

The tank looks very nice and doesn’t look anywhere near over stocked in my eyes and I love that leather coral, no way would I get rid of that. Although if I was a little closer I might recommend you do and give it to me! Lol

I guess you have several options including more fish, dosing nitrate etc so it’s a personal choice.

Thank you! I really do like that leather. I got it for far too cheap from an lfs that seems to get large corals in, then struggles to sell them.

For now I guess I'll continue dosing nitrate, but I'm going to back off a bit as @Mastiffsrule suggested. I got some reef roids that I'll use to target feed corals that are struggling a little more.

Eventually I'll probably add fish, but I need to find some "dirty" fish that increase the bioload more substantially, as I don't want to run out of territories by adding a lot of animals.

 

[Mastiffsrule]

If you do slow down the nitrate, just a tiny, tiny bit at a time. It is not just the leather using the nitrate, we don’t want a tank crash.

So I mean tiny for maybe 2 weeks to see how it responds. If you have been increasing I would stop at the last dose you put in and set that dose for the next 2 weeks. If you have been fairly consistent at a certain dose for a few weeks maybe back off .5ml of that. (That was a random amount based on a 10ml dosage or 5% since I am not sure how much you use). As mentioned a doser will really help here. Kamoer makes a doser set up for around 100$ if doable.

The other reason to go super slow is I would still like more input. Peace and salty had good points about the Po4 side. I am think the No3 side needs to be slowed down first. maybe
@Randy Holmes-Farley will see

 

[Indytraveler83]

If you do slow down the nitrate, just a tiny, tiny bit at a time. It is not just the leather using the nitrate, we don’t want a tank crash.

So I mean tiny for maybe 2 weeks to see how it responds. If you have been increasing I would stop at the last dose you put in and set that dose for the next 2 weeks. If you have been fairly consistent at a certain dose for a few weeks maybe back off .5ml of that. (That was a random amount based on a 10ml dosage or 5% since I am not sure how much you use). As mentioned a doser will really help here. Kamoer makes a doser set up for around 100$ if doable.

The other reason to go super slow is I would still like more input. Peace and salty had good points about the Po4 side. I am think the No3 side needs to be slowed down first. maybe
@Randy Holmes-Farley will see

Appreciate the suggestion on that. I've been using a formula that gets me 1 ppm once per day. I've made a concentrated solution, but then dilute it in top off water prior to topping off the sump. I was going to start dosing in the morning to, but I'll suspend that for now.

I think my real question boils down to this really: Is my NO3 consumption a result of rapid coral growth (such as the leather) and not enough bioload to support the coral's needs? Or is it due to something with the PO4 or something else I'm not quite grasping that's causing runaway NO4 consumption that needs to be arrested?

If it's due to coral growth, I'm happy to take the path of dosing and increasing bioload to support the coral. But I also don't want to be pushing along something I don't fully understand, especially if that's not the cause.

 

[Mastiffsrule]

The way you describe it, I would not change anything other than get an ATO to automate your top off and a doser for the No3. If you are diluting the No3 you may be able to even use the ATO as the doser. You would need to measure how much it adds per day to make sure it is adding the right amount but that should work too