Why do I have high nitrates but low phosphates?

[BlueCursor]

The ratio of N to P differs with each organism. 16:1 is based on one study. And to an earlier point, we don't test P at all. We only test organic P. The point to take away from this is we have to keep N much higher than P. I know from personal experience that if No3 dips below 1 while PO4 is 0.05, I have algae issues. With No3 at 2+ and PO4 at 0.05 I have no algae issues. We should look to what works in our tank based on this kind of logic because it's all we can test.

 

[Mpierce]

I have certainly been having some concerns with imbalance of nitrate and phosphate. I recently began dosing "vibrant" which is a bacterial product and it certainly seemed to eat nitrate at a very efficient level. As a result I ended up with near zero nitrate (red sea) but my phosphate levels were ~.12-.16ppm according to my hanna checker. I think this caused an explosion in cyano bacteria in my aquarium. After several weeks of trying to balance my nutrients with liquid phosphate removers and GFO I finally threw in the towel and used ultralife RSR which quickly knocked out my cyano, and I had no other negative effects. Now several weeks later I am having a few patches pop up again so I am back to checking my levels and trying to keep things balanced to see if I can prevent another outbreak.

There is a lot of good info/experiences on the vibrant thread about nutrient imbalance and bacterial (cyano especially) blooms.

-Matt

 

[nbagnardi]

When I started my system in Mar last year I thought near zero NO3 and PO4 was ideal however I know that is far far from the case. If it were even possible to feed corals as well as they are fed in the natural reefs, and it's not, I still believe there would be other problems with keeping NSW levels of NO3 and PO4. I had nothing but problems with NO3 <1ppm and my ideal number seems to be around 10. I try to keep the PO4 at .03 but that's difficult as I've stopped using GFO, it removes it too quickly. Now I use Phosphate RX and it's been working great. I also think the carbon part of the redfield ratio is important. With higher NO3/PO4 increased ALK/carbon is ok if not better. I have found that 10-11 dKH works well for me along with high intensity longer duration lighting. 2x Kessil AP700s and dual 60" T5 ATI Blue+, 85% 7 hours peak and 8 hour T5. That seems like a lot of light but with the AP700 there are no hot spots for my corals to get fried. I did have some bleaching issues when my NO3 was zero.

what size system are you running and how high are you cranking the ap700's if you don't mind me asking?

 

[LbulletM]

Great video. I'm currently trying to fight high nitrates. Good to remember to keep them in sync with each other.

 

[BlueCursor]

Being phosphate limited is more important than being nitrate limited, as far as algae control goes. So you definitely want to focus on limiting phosphate one way or another, either by using GFO or keeping nitrates high enough so they are not limiting.

 

[Nano sapiens]

The ratio of N to P differs with each organism. 16:1 is based on one study. And to an earlier point, we don't test P at all. We only test organic P. The point to take away from this is we have to keep N much higher than P. I know from personal experience that if No3 dips below 1 while PO4 is 0.05, I have algae issues. With No3 at 2+ and PO4 at 0.05 I have no algae issues. We should look to what works in our tank based on this kind of logic because it's all we can test.

I thnk you meant "We only test inorganic P" (aka 'orthophosphate').

 

[Monkeynaut]

I have certainly been having some concerns with imbalance of nitrate and phosphate. I recently began dosing "vibrant" which is a bacterial product and it certainly seemed to eat nitrate at a very efficient level. As a result I ended up with near zero nitrate (red sea) but my phosphate levels were ~.12-.16ppm according to my hanna checker. I think this caused an explosion in cyano bacteria in my aquarium. After several weeks of trying to balance my nutrients with liquid phosphate removers and GFO I finally threw in the towel and used ultralife RSR which quickly knocked out my cyano, and I had no other negative effects. Now several weeks later I am having a few patches pop up again so I am back to checking my levels and trying to keep things balanced to see if I can prevent another outbreak.

There is a lot of good info/experiences on the vibrant thread about nutrient imbalance and bacterial (cyano especially) blooms.

-Matt

What did you end up doing with this problem? I have the same issue now. 0 nitrate and .1 phosphate

 

[mcarroll]

I tried Vinegar and gfo for 35 weeks. Nitrates super high, PO4 almost zero.

Then the Dino's and red slime won the battle.

Elevating carbon in a nutrient-challenged tank is actually a little dangerous for the reason you experienced....there are competitors that specialize in that circumstance and they tend to be really nasty survivalists like dino's. Science calls them HAB's, or harmful algae blooms.

FYI, high nitrates were caused by the lack of PO4....bacterial growth (and lot of other things) gets stunted when the PO4 runs out. Dosing a little PO4 (like Seachem Flourish Phosphate or Brightwell NeoPhos) would have balanced things out and you'd have seen the NO3 spike evaporate.

Check out this thread and article for more info:
Dinoflagellates – Are You Tired Of Battling Altogether?
A Nitrate Dosing Calculator For Better Tank Health (And Better Coral Color!)

Going forward I'd recommend no more carbon dosing and keeping PO4 ≥ 0.10 ppm and NO3 ≥ 5-10 ppm to keep dino's from coming back.

 

[Dan Caldarona]

Great info. I've had my tank running for almost 6 months and after and alge outbreak I started running GFO. My Phosphate readings were 0 and my Nitrates would be 20ppm a week after a 25% water change. I had run my gravel vac down to the sump sock and deep cleaned the tank the other day and my Nitrates spiked. Even though I removed detritus and waste particulates, the elements remained in the water. At least I think that's my issue. Thanks!

 

[James Kanouff]

For a smaller tank "0-100 gallons" just do larger water changes to get it down its the cheapest way to get stabilized. No more GFO while your doing this. Be weary of how much food your feeding. That and old rocks are a common culprit for new reefers. Over stocking increases the issue with it as well. If you like DIY then I HIGHLY suggest a sulphur denitrator. there not complicated despite some posts, and they literally eat nitrate. Its a great solution for sea horse tanks where multi feeding per day pollute the tank with po4 and N03 much faster than the system consumes other items like ALK CA n MAG. Basically a sulphur denigrator targets n03. Its best to put the effluent into the skimmer intake section to re oxygenate the water and skim off the bacteria that come out the exit and die in the normal oxygenated water environment of the tank.

A very cheap and easy version is a BRS reactor fed with a simple MJ 900-1200 type pump, and A pair of "T" fittings on the in and out lines to add a second MJ pump for internal recirculation in the reactor. fill it full of sulphur pellets or add extra filler like ceramic bio cylinders or something if you don't need that much media for your small under 30 gallon type tank, "there not supposed to tumble inside" and a plastic clamp to restrict the out flow to a drop or two a second usually. More for larger tanks or higher N03 levels. If its smells like rotten eggs "sniff test the drip its very obvious" the drip is slow enough. No smell means slow it down more till water becomes anaerobic and the bacteria can begin processing the N03. It takes about 5-7 days to become anaerobic to begin with" usually you leave the drip completely closed to start the reactor" then basically runs for ever on its own or till the N03 runs out. Its easy to dial it in to a LOW safe level of n03 "not 0 which is too low and very possible" pretty quickly. This method does remove some ALK from the water in the process independent of other elements so you will need to dose a small amount of ALK maybe once a week or two or the water change will manage it. My tank is a 550 and I run 2.0 PPM of nitrate with about 2 gallons of sulphur pellets in an old Ca reactor that I capped the C02 part of the contraption and just use the in the out n the recirculation pump they come with to run the reactor in a loop while a small MJ pump drives the fed water thru to the drip end and into my skimmer intake. I take it apart once a year rinse it all out n restart it. Have never added pellets in three years. There is alot of builds on the forums and i recommend the internal recirculation versions because they tend to be more stable and smaller.

Let us know how it goes either way.

 

[Dan Caldarona]

So I decided to pull the GFO & Mechanical filtration (pad and floss). I added a big fist full of Cheating and popped a 60W 5000k led on the fuge. In 24 hrs my Nitrates dropped from 40ppm to 12ppm. I have no detectable Phosphate, but I think that will change and even out over the next week or so. There is a small amount of Cyano on the rocks in my tank. I think keeping the fuge lit 24hrs around the clock will help the Cheato out compete the nuisance algae. Today I'm happy.

 

[James Kanouff]

There is no way the cheato worked that fast. You must be having a testing error. Its possible the range of nitrates is drifting day to night a bit as well. but not more than maybe 2 -4 ppm My stable 550 tank builds 1 ppm Nitrate a day if i shut off my Sulphur denirator for example. and it never goes away on its own. There is no fuge. there is plenty of clean Live rock. i also deal with cyano alot with H202 but thats a different thing all together.

Id have fuge on when display is off to stabilize Ph swing to some degree. Id venture to say your fuge is large enough if you see very little ph swing based on the above comment about lights in other places of the system and algae growth.
24-7 lights on, is not any better for algae growth based on BRS did extensive tests on this in there algae srucbber series. 12 hours ish is the max it can do any good. it needs time to off gas. 60 watts will not be enough light either from my experience. Consider that your tank display is a giant bright Fuge in it self and if you want to create a better fuge location than your display, it must have more light and more flow to grow the algae in, instead of the display. Thats pretty simple deduction. Thats why they make the expensive fuge lights. I'd guess in a 20 gallon FUGE tank a 120 watt would be minimum to have significant impact and cost savings would be better spent on maybe water changes at those factors. 240 watts might be much improved and get closer to a real solution.

i also think you would most greatly benefit for some sort of filter sock or filter fleece and change it as often as you can. Judging by how clean everything is your just seeing new tank set up syndrome instability stuff. Everything needs to sort of come to balance and then you see in what part your system lay out lacks and then begin dealing with that issue directly.

mine for example is nitrate. Its the one thing i have to basically target to keep my water right. i have hundreds of varieties of corals and maybe 50 fish the tank is a dirty girl. i clean the foam filters and fleece once a week skimmer draws a gallon or two a week. and i do 25% Wc quarterly. then of course i dose my ALK MAG N CA as needed. The cost of using WC to deal with the No3 is too costly Vs the denirator method or the amount of lights and fuge space i'd need i think. But i have never built a 200 gallon 1000 what fuge and tried it. My main display has 1000 watts of light. In the 300DD and my three 60 gallon linked frag tanks each have 700 ish watts as well. if i want to grow algae somewhere it has to be similar flow and watts than those places basically or the algae will prefer the better flow and light locations and eventually take hold there instead. which is more theory than actual practice because you likely have tags n CUC n so forth but you get the point.

The oceans way of dealing with N03 is large anaerobic zones in sand and rocks and a reef tank typically can not duplicate that so we resort to alternate methods of consuming N03 with things like bio pellets reactors or large surface area media and rocks and aerobic bacteria "the least efficient ones" and water changes. Its very possible to over strip the water as well which i believe leads to cyano issues either from over skimming or unstable bacteria levels to some degree but thats something I'm learning to manage now in my systems and haven't figured out yet so its still theory for me.

 

[Japtastic]

BRS and this thread has hopefully lead me to the answer on why my cheato stopped growing after the first few months of my new tank setup and my nitrates getting really high @ around 80ppm. Fish only at the moment. I'm doing the Triton method so no regular water changes to bring them down that way. Regular water changes are a pain in the neck, slow and expensive for 340 gallons!

I always (wrongly) presumed my Phosphates were fine and so increased my light schedule from 12 to 16 hours in the fuge with the Kessil H380. I also dosed some Iron, based on other threads here.

At the same time I thought I better buy a decent test kit for Phosphate and check that as well, to my surprise, my Phosphates were completely undetectable with the Red Sea pro test kit so I ordered some trisodium phosphate and followed Randy's instruction to dose it and brought my Phosphate up to a tested 0.01ppm. Within 24 hours, this had gone back to undetectable so I have dosed again last night but this time to 0.04ppm. Will test again at the 24 hour mark to see what is going on.

 

[marcus aurelius]

So my 125 has been running for almost a year. I’ve tried everything and can not lower my nitrates bio load is small with only and hand full of fish 3 small wrasses 2 clowns 3 cardinals, lawnmower Blenny mandarin goby. Two months ago I added a bio pellet reactor and now no change. Using and Red Sea test kit for nitrates at 50+and seachem for phosphates.15. I have a eshopps sump with the small refugium. I’ve had a few fish die in the last couple months and some of my corals are not looking so hot. I’ve got red hair algae, bubble algae, and some green algae showing up.
Now what?

 

[randyBRS]

So my 125 has been running for almost a year. I’ve tried everything and can not lower my nitrates bio load is small with only and hand full of fish 3 small wrasses 2 clowns 3 cardinals, lawnmower Blenny mandarin goby. Two months ago I added a bio pellet reactor and now no change. Using and Red Sea test kit for nitrates at 50+and seachem for phosphates.15. I have a eshopps sump with the small refugium. I’ve had a few fish die in the last couple months and some of my corals are not looking so hot. I’ve got red hair algae, bubble algae, and some green algae showing up.
Now what?

With that low of a bioload (and what I assume to be an equally low nutrition input to feed them), effective skimming, regular maintenance, and steady water parameters this shouldn't be as large of an issue as you detail. It does seem rather abnormal, especially with a steady low nutrient input and increased nitrate/phosphate export. Perhaps it's time to look into a higher/more frequent amount of water changes, a more effective skimmer for that size of tank, a large and robust refugium with an effective lighting source like a Kessil H380, or a combination of approaches like these.

 

[nolifer]

So I've been looking into this topic and trying to work out why my nitrates are high and phosphates are low, my nitrates are 25+ mark and phosphates 0.04 I use the red sea mix reef recipe but not a lover of nopox product. I change filter socks every 2-3 days I feed red sea additives daily for corals and frozen for fish tank 140L after rock and sand I have nyos 120 skimmer. which I thought would be enough to remove the gunk. should I be looking into a fuge to help balance better? I only do 15L water change but find this needs to be increased to help bring down the levels of nitrate so would say it's like 60-70L water change to even make a dent on levels.

 

[Japtastic]

So I've been looking into this topic and trying to work out why my nitrates are high and phosphates are low, my nitrates are 25+ mark and phosphates 0.04 I use the red sea mix reef recipe but not a lover of nopox product. I change filter socks every 2-3 days I feed red sea additives daily for corals and frozen for fish tank 140L after rock and sand I have nyos 120 skimmer. which I thought would be enough to remove the gunk. should I be looking into a fuge to help balance better? I only do 15L water change but find this needs to be increased to help bring down the levels of nitrate so would say it's like 60-70L water change to even make a dent on levels.

Working out the cause is what I’d try to figure out first.

Have you skipped water changes regularly?

How long has the tank been setup?

How many times a day are you feeding for what fish? Do you think you could be over feeding?

Of course your maintenance/feeding etc may be fine now and you just need to deal with the excess Nitrates stored up.

I would do a number of 10% water changes every other day until you have the Nitrates where you want them. You may have stored up Nitrates in your rock etc so it may take a lot longer than you think.

Once you are there, it’s going to be a lot easier to keep them there going forward. This is all based on what I’ve learned over the last few months so all imo. Good luck!

 

[KCSUMPS]

Great explanation. This makes sense to me as I have had the same problem with a 16 year old tank. I tried Vinegar and gfo for 35 weeks. Nitrates super high, PO4 almost zero. I replaced 90% of the the gravel, and was doing 30% weekly water changes. Then the Dino's and red slime won the battle. One year later I'm going with a well light fuge with cheato, and small (3% weekly) but frequent water changes. I also only scrapped the front glass clean, and am not super cleaning the tank at once, skimmer backed all the way down. Small sections per week get cleaned. I don't want to kill the red algae and have something worse take over (dino's). Im hopeful the cheato will take over and outcompete everything else. So far so good three weeks in.

Thank you for the video and explanations.

did your refugium do it?

 

[KCSUMPS]

Thank you Randy.
I don't have the space for the new Sump/Refugium. I had to find a place and its 5 meters away and plumbing would be impossible as it would be very expensive to hide the tubing.
I'm getting a 180 G tank that will house the Sump/Refugium below and its a much better investment.
The program with DOS will exchange between DT and Sump. I think that the macroalgae and the DSB will be able to process all the nitrate and phosphate and the water returning to the DT will be almost as new. I also think that this way the S/R will not accumulate any sediments coming from the DT only perfect clean water with NO3 and PO4. This way the Chaeto and the Deep Sand Bed will eventually take care of all the nitrates and phospates tha DT can't process.
I could eventually stop using GFO and Biopellets or reduce the use of it for a more natural way.

how did it end up for you?

 

[Skynyrd Fish]

did your refugium do it?

Yes. It worked great. I am dosing Nitrate in my make up water now to keep PO4 down. However,since my original post, my tank maintenance guy unplugged my heater, and my tank was at 68 degrees before I caught it 2 weeks later. Dory died, SPS stopped taking up ALK and CA, and I started getting a hair algae issue. I also noticed an absence of small pods. After 6 weeks the hair algae started killing my sps. I did stop all dosing except ATI essentials. It has been a slow turn around since May, my fuge is now starting to grow macro again. My last ICP test end of August said NO3 = 0 PO4 = .03 I almost took the tank down I was so fed up. I lost 40 frags, my purple tang and my blue tang. Sorry about my rant. Fuge yes.