Low PO4 and rising nitrates

[Bilk]

Figured I'd post this here as well. No responses in the Chem forum. Maybe someone here can help or offer suggestions.

Seems the nutrient levels in my tank are out of balance. Using a Hanna 736, the measurable levels of PO4 are anywhere from 0 - 4ppb. I have 6 boxes of regents and use a packet from a different box for each test. They come from two different lots. The testing results are consistent. I do not use any phosphate media.

On the other side, NO3 is on the rise, reading +5ppm. I have a RSP kit. Using the diluted method of 1ml sample to 15ml of RO water, the test shows it's over 4ppm, but not quite 8ppm, so the actual number is not definitive. It has been rising since the low levels of PO4 have been exhibited.

Other parameters for alk and PH are 7.5dkh and 8.12 - 8.35 respectively.

There's very little algae growth in the tank at this point, but the glass does get a brown algae haze, vs a green. The corals are showing little PE and the colors are darkening. I'd like to address this before things are well out of balance and the issue is tougher to recover from.

I've done some larger water changes - daily 10% for a few days successively, and this hasn't helped so far. I do feed a lot - generally only frozen foods and was rinsing, but since have stopped thinking that any additional phosphate in the food would help. So I'm looking for some ideas from the forum. Anyone else have this sort of problem or have an idea of how to correct this?

Adding - I was carbon dosing VSV, but since this imbalance was discovered, I've stopped. The dose was 7ml/day for a system volume of approximately 195g.

 

[CHSUB]

I had a very similar issue; very low or unreadable po4 (Salifert, Milwaukee photometer, API) with slowly increasing NO3: pale corals, little or no growth, and STN over nearly a year. The fix for me was to stop vinegar. Corals are growing and coloring: parameters are po4 @ .015 and no3 @ 2.5 and steady for 2 months without vinegar. Algae are growing on the glass and have a greenish/brown tint, similar to what I was accustom to when corals grew well. With vinegar I would only get a white powder on the glass every 5 days. IMO and IME if green/brown algae are not growing on your glass, your corals symbiotic zooxanthellae are starving.

 

[Bilk]

I had a very similar issue; very low or unreadable po4 (Salifert, Milwaukee photometer, API) with slowly increasing NO3: pale corals, little or no growth, and STN over nearly a year. The fix for me was to stop vinegar. Corals are growing and coloring: parameters are po4 @ .015 and no3 @ 2.5 and steady for 2 months without vinegar. Algae are growing on the glass and have a greenish/brown tint, similar to what I was accustom to when corals grew well. With vinegar I would only get a white powder on the glass every 5 days. IMO and IME if green/brown algae are not growing on your glass, your corals symbiotic zooxanthellae are starving.

I understand that idea but the corals in this instance, have good colors. None are pale. Here's a recent pic.

I'm just worried that nitrates will continue to rise and get out of control. I'm also not happy there's not much PE happening, though looking today, there's seems to be more.

So you just let everything level off and find it's own balance? I stopped rinsing cubes. Just thaw them in tank water and throw them in now. Thought the additional PO4 might help bind some of the nitrates in the bacterial action and get skimmed.


Have to add, zoos are closed up and don't look good. LPS are doing fine.


.........................................................................................

 

[CommsTech]

Have you thought about the redfield ratio? It says nutrients will be used up at a ration of 106:16:1 carbon:nitrate: phos

If your phosphate is too low then nitrates may not be being processed. I had to dose nitrates to my tank to get things working properly. Perhaps you may need to dose PO4 to get things back in check, Although doing so you would have to be very cautious and precise. Just a thought...

 

[Bilk]

Have you thought about the redfield ratio? It says nutrients will be used up at a ration of 106:16:1 carbon:nitrate: phos

If your phosphate is too low then nitrates may not be being processed. I had to dose nitrates to my tank to get things working properly. Perhaps you may need to dose PO4 to get things back in check, Although doing so you would have to be very cautious and precise. Just a thought...

That's exactly what I thought about and why I'm concerned. It's also why I stopped carbon dosing for now, until I can sort thru this, if there's anything to sort thru. Maybe it will stabilize on it's own. I'm just going to keep watch NO3 for changes.

 

[Eastone]

What do you do for po4 removal? If running GFO I'd suggest removing it, if not I'd suggest dosing phosphate very mildly. I use the Easy Life plant fert for dosing nitrate and phosphate

 

[Bilk]

What do you do for po4 removal? If running GFO I'd suggest removing it, if not I'd suggest dosing phosphate very mildly. I use the Easy Life plant fert for dosing nitrate and phosphate

I was carbon dosing. No GFO or other phosphate media.

So how do you determine your dosing?

Right now, after stopping carbon and letting things settle, PO4 has remained at the very low end, but NO3 has dropped a little and in a pretty solid 4ppm, which is lower than it was a few days ago. It was closer to 8ppm using RSP in high range test. Hopefully it finds it's own comfortable balance, but open to trying phosphate dosing. I have a bottle of Seachem Flourish which is 4500ppm. I haven't tried it yet. Worried it will foster nuisance algae. Finally have all of that taken care of. Just a few stragglers of valonia which I pick out when I see them. My foxface and regal tang nibble on the small vesicles from time to time which helps. Foxface picks them from the rocks. The tank will gobble them up if they become dislodged and hit the water column.

 

[Eastone]

hmm if you're carbon dosing I'd then suggest trying a bottle of bacteria culture - something like Zeobak or microbacter7 or whatever it's called. Often in carbon dosing situations you end up with a monoculture which can result in nutrient imbalances long-run.
What is your carbon source?
With nitrate and phosphate I use my coral appearance - too light or dark means nitrate isn't right and a slowing of growth or thinning base tissue is too much / little phosphate. I'd recommend starting extremely low when dosing phosphate, changes in this have very negative effects on SPS

 

[Bilk]

hmm if you're carbon dosing I'd then suggest trying a bottle of bacteria culture - something like Zeobak or microbacter7 or whatever it's called. Often in carbon dosing situations you end up with a monoculture which can result in nutrient imbalances long-run.
What is your carbon source?
With nitrate and phosphate I use my coral appearance - too light or dark means nitrate isn't right and a slowing of growth or thinning base tissue is too much / little phosphate. I'd recommend starting extremely low when dosing phosphate, changes in this have very negative effects on SPS

Again, I stopped the carbon dosing more than a week ago (maybe two now- I'd have to check my records), when I saw PO4 was near zero on a regular basis with the Hanna ULR.

I've been dosing Microbe-Lift and Prodibio after seeing Richie's/Jackson's tank He has that dialed in and humming.

I have to say, water clarity has increased, since doing so. My filter socks are also staying cleaner longer.

I'm going to let this ride for a bit since NO3 has seemed to level off and actually come down. PO4 hasn't changed, but I'll keep an eye on the corals. No fading or recession so it looks good so far.

 

[Johnyman]

I had the same issue and i solved it by adding phosphate potassium and control the phosphate around 0.01-0.03 and with carbon source dose i drop nitrate from 50ppm to 2ppm in 5 weeks!! Things look better now, including the cyano recession.

 

[markalot]

Hi Bill,

I would back off carbon dosing until they balance out. Sounds like carbon dosing has driven PO4 too low and now nitrates start to rise. The solution, IMO, is to lower carbon dosing until it's not enough to keep PO4 low at which point you should start to see NO3 drop.

The big question is, are you adding more PO4 or Nitrates to the tank? I think some dirty flake food would be a perfect solution, something with a lot of PO4, rather than dosing PO4.

My inexperienced opinion. I'm on the nitrate side of things and am controlling PO4 by dosing CaNO3 and it works great.

 

[Pife]

How's the tank doing now that it has been a couple months? I had this issue and dosed a lot of Aqua vitro fuel. I now have a balanced tank again.

 

[markalot]

Good grief, it has been months.