How to manage nitrate trending down and phosphates going up effectively?

[Kenneth Wingerter]

Unfortunately, my nitrates are now at 0.0, while my phosphates slightly increased to 0.22 (up from 0.19).

I increased the daily dosing amount for Elimi NP from 0.1 ml /100l to 0.2 ml /100l, which most likely contributed to/caused this issue. Also, it proved that this product is more effective in reducing Nitrates than eliminating Phosphates, at least in the short term.

Therefore, I am in emergency mode and must raise nitrates while still trying to reduce phosphates ASAP (relatively speaking).

Can you please let me know if the below sound reasonable actions:

1. Dose Nitrates with a supplement. I will choose Brightwell Neonitro (seems as if this is a reliable product).
2. Take off the skimmer cup until Nitrates are at a reasonable level - for me, 2-10 seems fine when I had that and looking at corals. Will this still reduce my Phosphates?
3. Restart dosing of Phosban (Lanthanum Chloride). I have been using a very low amount over several days and had good short-term results in the past, typically reducing them by 0.08 ppm in 4 days.
4. Water change - should I stop water changes until Nitrate is back up?
5. Phytoplankton? Stop dosing 5 times a week? Until Nitrate is back up?
6. PNS Pro Bio? Stop dosing once a week? Until Nitrates is back up?

Thank you!

I don't believe that there's an emergency to respond to with respect to the very low NO3 concentration. In the wild, healthy natural coral reefs are usually nitrogen limited (in other words, growth is restricted by availability of 'fixed' forms of inorganic nitrogen such as ammonia and nitrate). Corals are very well adapted to these conditions; it is, on the other hand, phosphorus limitation that causes them severe stress. Of course, the required amount of phosphorus is quite a bit less than what is available in a typical aquarium environment. Something like 0.03 ppm is plenty, so your effort to reduce current PO4 levels does make sense.

Firstly, be aware that corals (their zooxanthellae, more specifically) very much prefer ammonia to nitrate. By adding nitrate, you might be fueling undesirable algae growth more than anything else. I'd stick to the old-school advice to maintain as low NO3 concentrations as possible. I realize that's subject to very hot debate, and that's okay with me--just my opinion.

I can speak more directly to your questions about PNS ProBio, as I manage Hydrospace LLC. Despite the fact that the bacterium in that product, Rhodopseudomonas palustris, is a denitrifier and can potentially remove nitrate, there would be no reason to stop using it for the reason you stated. That's because the species is also a nitrogen fixer, meaning that when biologically available nitrogen sources become low, it literally creates ammonia from nitrogen gas. The coral then obtains fixed nitrogen from eating the zooxanthellae (which scavenge some of the 'leaked' ammonia) or from eating the bacteria themselves. Like a relatively small handful of other nitrogen fixers, R. palustris is known to associate with corals often and is indeed considered by many coral biologists to be a symbiotic partner (with both coral and zooxanthellae). If you're unfamiliar with this relationship, here's a short article that sums it up. A more detailed description of coral-associated R. palustris and other nitrogen fixers may be found in CORAL Magazine Vol 18, No 4 ("Meet the Diazotrophs").

R. palustris may actually be quite beneficial in your case. In addition to potentially providing nitrogen to the corals (by both fertilizing the zooxanthellae and by feeding the coral that eats it), these bacteria also are especially good at removing phosphate. The species is in a class of microbes called 'phosphate accumulators' owing to its ability to remove far more PO4 than it needs for that moment's growth, storing it inside its body as polyphosphate granules. I've seen this myself in experimental cultures (assuming PO4 accumulation), where the amount of PO4 utilized greatly exceeded its Redfield requirement. When removed via skimming, these bacteria can export far more PO4 than other bacterioplankton.

So yeah, maybe it's no surprise that I'd recommend continuing to use our product, but I sincerely see no good reason to stop dosing ProBio (and think it could very well help you, actually).

 

[Alexander1312]

I don't believe that there's an emergency to respond to with respect to the very low NO3 concentration. In the wild, healthy natural coral reefs are usually nitrogen limited (in other words, growth is restricted by availability of 'fixed' forms of inorganic nitrogen such as ammonia and nitrate). Corals are very well adapted to these conditions; it is, on the other hand, phosphorus limitation that causes them severe stress. Of course, the required amount of phosphorus is quite a bit less than what is available in a typical aquarium environment. Something like 0.03 ppm is plenty, so your effort to reduce current PO4 levels does make sense.

Firstly, be aware that corals (their zooxanthellae, more specifically) very much prefer ammonia to nitrate. By adding nitrate, you might be fueling undesirable algae growth more than anything else. I'd stick to the old-school advice to maintain as low NO3 concentrations as possible. I realize that's subject to very hot debate, and that's okay with me--just my opinion.

I can speak more directly to your questions about PNS ProBio, as I manage Hydrospace LLC. Despite the fact that the bacterium in that product, Rhodopseudomonas palustris, is a denitrifier and can potentially remove nitrate, there would be no reason to stop using it for the reason you stated. That's because the species is also a nitrogen fixer, meaning that when biologically available nitrogen sources become low, it literally creates ammonia from nitrogen gas. The coral then obtains fixed nitrogen from eating the zooxanthellae (which scavenge some of the 'leaked' ammonia) or from eating the bacteria themselves. Like a relatively small handful of other nitrogen fixers, R. palustris is known to associate with corals often and is indeed considered by many coral biologists to be a symbiotic partner (with both coral and zooxanthellae). If you're unfamiliar with this relationship, here's a short article that sums it up. A more detailed description of coral-associated R. palustris and other nitrogen fixers may be found in CORAL Magazine Vol 18, No 4 ("Meet the Diazotrophs").

R. palustris may actually be quite beneficial in your case. In addition to potentially providing nitrogen to the corals (by both fertilizing the zooxanthellae and by feeding the coral that eats it), these bacteria also are especially good at removing phosphate. The species is in a class of microbes called 'phosphate accumulators' owing to its ability to remove far more PO4 than it needs for that moment's growth, storing it inside its body as polyphosphate granules. I've seen this myself in experimental cultures (assuming PO4 accumulation), where the amount of PO4 utilized greatly exceeded its Redfield requirement. When removed via skimming, these bacteria can export far more PO4 than other bacterioplankton.

So yeah, maybe it's no surprise that I'd recommend continuing to use our product, but I sincerely see no good reason to stop dosing ProBio (and think it could very well help you, actually).

Very helpful Kenneth, thanks so much for this detailed response. Should I actually increase the use of ProBio then to e.g., multiple times per week until Nitrate and Phosphate are back in balance? I appreciate I am asking the seller here but I trust your answer. And this might be a stupid question but adding the skimmer cup back in or leave it out when doing that?

 

[Kenneth Wingerter]

Very helpful Kenneth, thanks so much for this detailed response. Should I actually increase the use of ProBio then to e.g., multiple times per week until Nitrate and Phosphate are back in balance? I appreciate I am asking the seller here but I trust your answer. And this might be a stupid question but adding the skimmer cup back in or leave it out when doing that?

Awesome, thanks. You could definitely increase the dose. You can use up to the max recommended dose of 1.25 ml/gal daily. Gradual increases are fine and may help you to find the Goldilocks dose for your particular system, though there is no real risk of overdose. Like most biological methods, this stuff works pretty slowly anyway (which generally is a good thing).

Yes, I'd continue using the skimmer as normal, particularly if you wish to export microbial biomass (i.e., reduce phosphate).

 

[Randy Holmes-Farley]

Yes, that’s a fine one.

Use this calculator and the entry for nitrate from potassium nitrate, which is close enough.

James' Planted Tank - Dosing Calculator