Another nitrate and phosphate question

[Fishingandreefing]

My phosphate is .17 and nitrate is 12. I want to lower my phosphate to around .10 and raise my nitrate to 15. I will use other methods to deal wirh that but should I leave my lights in the refugium longer or shorter for my caulerpas? Currently running 17 hours.

lastly, I have heard that if nitrate raise at a certain point, phosphate will drop but at what ratio? When my nitrate at 15-20?

 

[Randy Holmes-Farley Verified Community Expert]

I'd have to say that targeting 15 ppm nitrate and being at 12 and wondering how to do it is really pushing beyond the accuracy of our test kits, or the likely ability to notice any change in the tank if you accomplished it.

Raising nitrate will not likely impact your phosphate because there is already more than enough there for it to not be limiting growth.

To make these changes, the best ways are to somehow add N (feed more or dose nitrate) and consume more P, such as with a phosphate binder, or maybe longer or brighter refugia lighting (may not work), or larger area of macroalgae.

 

[workhz]

Randy. What levels would you say would limit growth on the nitrate side?

 

[Randy Holmes-Farley Verified Community Expert]

It's a complex question since the exact answer will depend on availability of other nutrients, iron, etc., but I've not see any ocean studies that suggest that nitrogen availability limits phytoplankton or algae when nitrate is above 10 ppm.

Most dosing studies in the ocean are looking at levels like 1 ppm.

 

[J1a]

In addition to nitrates, ammonium can also be a good source of nitrogen for the corals. It can be readily taken up by corals and clams.

I would think an undetectable nitrate with a strong ammonium flux is really ideal for coral aquarium.

 

[Fishingandreefing]

I am raising it by neonitro and prob will drop it slightly by lanthanum but I am still using caulerpas. So since I am running a 17 hours schedule, should shorten the time or leave it?

 

[Randy Holmes-Farley Verified Community Expert]

I am raising it by neonitro and prob will drop it slightly by lanthanum but I am still using caulerpas. So since I am running a 17 hours schedule, should shorten the time or leave it?

I'd leave it.

 

[Randy Holmes-Farley Verified Community Expert]

In addition to nitrates, ammonium can also be a good source of nitrogen for the corals. It can be readily taken up by corals and clams.

I would think an undetectable nitrate with a strong ammonium flux is really ideal for coral aquarium.

Possibly.