Can I reduce PO4 without dosing NO3 using PNS PROBIO

[reefluvrr]

Hi @Kenneth Wingerter

I am running a sumpless 13 gallon reef tank mainly with mushrooms, but there are couple acan LPS and one green gonipora LPS.

I have this tank up and running since January of this year. I used live rock from my main reef tank and live sand as well on day one for this tank. I seeded this tank with copepods and it has been doing very well since day one.

I have 0 Nitrate in this tank, and I do not know if I have enough Nitrogen source from my 4 fishes in the tank.
However, my PO4 is through the roof at 0.68 in this tank.

There is green algae which I have to scrape off the glass almost daily.


Can I just dose PNS PROBIO into this tank and expect my PO4 to drop without adding NO3?

As you have mentioned in your youtube videos. Corals don't use NO3 as much as other sources of Nitrogen such as ammonium.
Hans Werner at Tropic Marin also doesn't care for dosing NO3.

Therefore I am hoping I can reduce my PO4 with PNS ProBio utilizing fish waste such as ammonium, urea, etc.

Can you share your thoughts on this and help possibly explain the mechanism for it?

Thank you.

 

[Kenneth Wingerter]

Hi @Kenneth Wingerter

I have 0 Nitrate in this tank, and I do not know if I have enough Nitrogen source from my 4 fishes in the tank.
However, my PO4 is through the roof at 0.68 in this tank.

Can I just dose PNS PROBIO into this tank and expect my PO4 to drop without adding NO3?

The answer, I suppose, is 'maybe.' That depends on the rate of growth as well as the rate of nitrogen fixation. The ultimate population size will depend on how much the bacteria are pressured by competing microbes, as well as the rate at which they are grazed by corals, copepods, bivalves and other picoplanktivores. Additionally, factor in that they prefer anaerobic habitats and higher temps, which will increase the population carrying capacity and growth rate respectively. Carbon dosing an acetic substance such as vinegar increases both. Both nitrogen and phosphorus are exported as the young, motile daughter cells are removed via skimming.

More to your point regarding high PO4/low NO3, remember that these organisms are nitrogen fixers. When NH4/NO3 is scarce, these bacteria convert nitrogen gas (N2) into NH4 (essentially the reverse of denitrification). Therefore, while most bacteria would be useless for removing PO4 in these conditions, these bacteria can adapt and carry on. That is, so long as they can successfully invade/colonize a substantial area of anaerobic habitat (they can only perform nitrogen fixation in anaerobic conditions).

While your PO4 may be too high for your liking (inhibiting stony coral growth, for example), these conditions are in essence what you'd find on a typical natural reef--where nitrogen is limiting and there is a relatively small, albeit adequate, concentration of PO4. Many coral biologist suggest that these conditions are the main reason reefs aren't covered in algae, the competitor of corals. Corals nevertheless thrive owing to their symbiotic relationship with nitrogen fixers. In other words, nitrogen is limiting outside the coral polyp (i.e., the water column) but not within the polyp itself.

So these bacteria (e.g., Rhodopseudomoans palustris) can live in two places, in the substrate/biomedia and in the coral. The former is where you'll potentially achieve the most phosphorus removal (export via skimming), though the latter is also interesting and worthy of mention.

 

[reefluvrr]

I have quite a bit of biobricks on the back of my sump and nothing else. I do not run a skimmer in this tank.
If I have the phosphorus bound up in the bacteria, this in essence becomes organic phosphate food for my corals right? I would like to strive to have a tank high in organic phosphate. How do you keep your skimmerless tanks lower in PO4 levels?

Can you also give me some insight as to how much of R. palustris may live in stony corals vs soft corals?