Tropic Marin Plus-NP lowering my nitrates

hogger555 · Nov 8, 2020

I started dosing Plus-NP 3 days ago, before dosing my phosphate was undetectable and nitrate was 5 ppm. Now phosphate still undetectable and nitrate is as well. I get why phosphate is still 0 because it's probably all going into my rock and sand, but why have my nitrates dropped? I haven't changed anything else since I started dosing, no water changes either, and no refugium or algae reactor. I do run my protein skimmer 24/7. Only have 4 clownfish and a handful of SPS and LPS frags I just added so no big nutrient intake. I'm using Salifert tests. Any info is appreciated!

Flippers4pups · Nov 10, 2020

hogger555 · Nov 10, 2020

I contacted Tropic Marin and here is their response:

I can assure you that you have done nothing wrong. What you are seeing is normal with Plus-NP. Most of the nitrogen in Plus-NP is not in the nitrate form but in ammonium and organic form. Phosphate is also added in a form that cannot be measured with normal test kits readily but is bioavailable to the corals and other marine organisms. The nutrients are dosed in an organic matrix that supports the conversion of some of the nutrients to bacterial biomass which is available to the corals as well. The background of this unconventional approach is, that nitrate is not the best form of nitrogen for corals and may even have adverse effects, and phosphate in the form of orthophosphate readily adsorbs to calcareous materials and is not available to corals any more. We avoid these problems by our unconventional approach, but with the drawback that the nutrients cannot be found by testing readily.

We recommend to watch the corals in order to assess the effect of the nutrient supply. After some days the phosphate will show up in testing and we have adjusted our recommendations to the phosphate supply only.

Kind regards

Hans-Werner Balling

tdyrkacz · Mar 17, 2022

Interesting. On their directions for Plus NP they state to stop dosing once desired Nitrate and Phosphate level has been achieved... but if you can't test for it then how will you know?

Dennis Cartier · Mar 17, 2022

You will know because any unused excess will eventually get converted to their inorganic forms and show up on test kits.

Best case scenario would be that your corals have a nice growth spurt and you never see your nitrate or phosphate readings move. That would indicate your addition is getting fully utilized and is not accumulating.

Reef_Curiosity · Mar 17, 2022

tdyrkacz said:
Interesting. On their directions for Plus NP they state to stop dosing once desired Nitrate and Phosphate level has been achieved... but if you can't test for it then how will you know?

Hi,

The dosing of Plus-NP is not the only way phosphate and nitrogen enter the aquarium. There are also the foods you feed the fish.
So, if your regular feeding is not enough to cover the uptake of N and P by the corals etc, you can add more with Plus-NP, which is preffered by the corals. This means that regular waste products, NO3 and PO4, have a chance of increasing to a point where the aquarium is not phosphate limited, and you can focus on maintenance dosing instead with a different product.