High Phosphates but no nitrates?

[Crabs McJones]

So I tested my parameters last night. I'll admit I haven't done it in a while aside from Calcium and Alkalinity. I used the Hannah ULR phosphate tester, and the Salifert Nitrate tester. My results came back at .36ppm phosphate, and I could not see any color in the Salifert Nitrate test (both from top down and from the side) so i'm lead to assume its less than 2ppm - 0 nitrate. Everything in the tank looks fine. I have been feeding heavier to get my nitrate levels up, but it appears that only my phosphates have climbed. Should I be concerned? My chaeto in my fuge is still going strong with no issues. (I tested phosphates twice just to make sure I didn't mess up, and both came back with the exact same result)

Thoughts? Suggestions?

Thanks

Crabs

 

[saltyfilmfolks]

Looks ok , is ok.

 

[andrewkw]

I would not be overly concerned. Especially if everything looks fine. What do you want to look good your corals or your test results? That being said I would be more concerned with .36 phosphates then 0 nitrates, but on a scale of 1-10 I would give it a 2 or 3 at the most.

 

[KrisReef]

I've been having a similar situation with nutrients, my Phosphate numbers grow as I feed but Nitrate is low. I've increased GFO to try and keep Phosphate from getting too far out. I increased feeding and did a little N dosing to get Nitrate to read, and have been keeping an eye on the minor algae & red slime growth that is showing on the edges.

The corals seem ok, mostly, with only a few SPS not looking happy and the LPS and mushrooms and the well fed fish very glad that I've let the tank get so dirty.

I think this is better than zero's, but I am keeping a watchful eye out for an algae explosion or similar negative results.

 

[andrewkw]

One more thing : If I were you I would not do anything drastic. The best thing you can do is test a few more times for a few more weeks. As you mentioned you hadn't tested in a while. You can't be sure how long the parameters have been similar. Once you determine if phosphate is still going up and nitrate is bottomed out at 0 you will have a better idea how to proceed.

 

[DLHDesign]

Your denitrifying bacteria population is strong, but your phosphate uptake (coral growth, algae growth, and other biological processes/growth) is behind the curve compared to your phosphate input. If you're growing algae somewhere (fuge, scrubber, etc.) you could up it's photoperiod and/or intensity, but that may throw off other things as well. Other option is to run one of the various phos-removal products. I've not had any experience with those, however...

Or, you know, don't worry about it. :-D

 

[Crabs McJones]

Your denitrifying bacteria population is strong, but your phosphate uptake (coral growth, algae growth, and other biological processes/growth) is behind the curve compared to your phosphate input. If you're growing algae somewhere (fuge, scrubber, etc.) you could up it's photoperiod and/or intensity, but that may throw off other things as well. Other option is to run one of the various phos-removal products. I've not had any experience with those, however...

Or, you know, don't worry about it. :-D

I did up my fuge photoperiod recently, but I also pruned back my chaeto quite a bit and sent it to another user. That might be the reason behind my upped phosphates. But doesn't explain the nitrates. I'm not going to take any action at this time.

 

[saltyfilmfolks]

Your denitrifying bacteria population is strong, but your phosphate uptake (coral growth, algae growth, and other biological processes/growth) is behind the curve compared to your phosphate input. If you're growing algae somewhere (fuge, scrubber, etc.) you could up it's photoperiod and/or intensity, but that may throw off other things as well. Other option is to run one of the various phos-removal products. I've not had any experience with those, however...

Or, you know, don't worry about it. :-D

No3 is more easily removed and no3 used in higher quantities. Little to due with slowing growth imo.

 

[Randy Holmes-Farley Verified Community Expert]

I personally might consider nitrate dosing, both to help reduce the phosphate as the algae take up both, and to decrease the chance of a pest like dinos.

 

[Crabs McJones]

I personally might consider nitrate dosing, both to help reduce the phosphate as the algae take up both, and to decrease the chance of a pest like dinos.

Nitrate dosing would be a brand new field for me, any suggestions? ELI5

 

[cracker]

Just go slow with the dosing it's easy to over shoot your target number.

 

[Crabs McJones]

Just go slow with the dosing it's easy to over shoot your target number.

I don't know how comfortable i'd be with nitrate dosing. I'm considering just a series of water changes to bring phosphates down and let it be

 

[theMeat]

I personally might consider nitrate dosing, both to help reduce the phosphate as the algae take up both, and to decrease the chance of a pest like dinos.

Agree with this. Except since the parameters are imo within range, just not ideal, would use natural method, like turning down light time on fuge, instead of dosing.
Getting nitrates up will help with phosphate. Turning up the light time on fuge will get you further into the hole. Because fuge consumes a higher ratio of nitrate to phosphate. Which aside from other factors like coral uptake, is probably the cause of your situation.

 

[Mical]

I find when I prune my cheato phos climbs a little

 

[Stickboy15]

@Crabs Mcjones whats your fish load? I would also maybe trim the cheato. I have the same issue low nitrates but po4 0.10 I can’t tell you what does it but I never mess with it as long as corals are growing and not a ton of algae in the tank I’d say leave it alone. It’s not worth chasing numbers just gonna get the tank chemistry unstable.

 

[Randy Holmes-Farley Verified Community Expert]

I don't know how comfortable i'd be with nitrate dosing. I'm considering just a series of water changes to bring phosphates down and let it be

Water changes are usually not especially effective for phosphate because of the large reservoir bound to rock and sand that come off when you drop the level in the water.

 

[Randy Holmes-Farley Verified Community Expert]

Agree with this. Except since the parameters are imo within range, just not ideal, would use natural method, like turning down light time on fuge, instead of dosing.
Getting nitrates up will help with phosphate. Turning up the light time on fuge will get you further into the hole. Because fuge consumes a higher ratio of nitrate to phosphate. Which aside from other factors like coral uptake, is probably the cause of your situation.

I don't see how reducing lighting on the refugium would decrease phosphate in a situation like this.

If, as you suggest, it allows nitrate to rise (likely true), then it is also exporting less phosphate.

 

[theMeat]

I don't see how reducing lighting on the refugium would decrease phosphate in a situation like this.

If, as you suggest, it allows nitrate to rise (likely true), then it is also exporting less phosphate.

Didn’t say less light would lower phosphate. Said it would raise nitrates. Is there any scientific proof that raising nitrates could lower phosphate?
Kalk can help lower phosphate too. Pretty sure there’s no proven evidence of this but it is thought, and i’m A believer

 

[Stickboy15]

Didn’t say less light would lower phosphate. Said it would raise nitrates. Is there any scientific proof that raising nitrates could lower phosphate?
Kalk can help lower phosphate too. Pretty sure there’s no proven evidence of this but it is thought, and i’m A believer

I feel less cheato would help more then less light because when you mess with the lighting if he runs his fuge at night to keep his ph up so then he will be dealing with ph issues if he’s on a reverse cycle

 

[theMeat]

I feel less cheato would help more then less light because when you mess with the lighting if he runs his fuge at night to keep his ph up so then he will be dealing with ph issues if he’s on a reverse cycle

Good point
Fuge lighting can help with ph swings. Most people run fuge light 14 hours to overlap display. Could lessen the overlap time with minimal effect to ph. Maybe even better, depending on display light vs fuge light