Is nitrate necessary for phosphate reduction?

[DannyB]

My test results show i have <.2ppm nitrate (Salifert test kit only the slightest tint of pink nowhere near the 0.2ppm color) and phosphorus 11ppb, phosphate 0.033ppm (Hanna ULR) and have struggled with getting the phosphates lower than 0.03.

Do nitrates need to be present for phosphate reduction?

I use the Zeovit system for nutrient export.

 

[Randy Holmes-Farley Verified Community Expert]

If you use something like GFO or aluminum oxide, no nitrate is necessary at all for phosphate reduction.

If you use something like growing macroalgae or bacteria (when organic carbon dosing) or simple growth of tank organisms, then yes, some nitrate is needed for these organisms to grow. More, in fact, than phosphate.

Organic carbon dosing (like zeovit, vodka, vinegar, etc.) is actually overbalanced toward too much nitrate reduction relative to phosphate (compared to foods) and often result in left over phosphate that remains even if nitrate is driven down very low. To get around this, you can use a phosphate export method like GFO that uses no nitrate, or you can add nitrate and allow a mixed method to export more of both.

 

[eQuatics]

To help you understand, nitrate and nitrite contain oxygen and nitrogen elements, phosphate contains negatively charged ions phosphorus, oxygen and at least one of them being hydrogen. So since they have very similar elements, the short answer is no, however commonly you'll find nitrate in your tank when phosphate is present. You may not be able to test for it as the nitrate may be hiding in algae, corals, or even in the phosphate itself.

Good rule of thumb is to have zero of both lol. No two tank is alike!

 

[jason2459]

0.03 is already pretty low. What does zeovit or you want that number to go down to?

 

[Randy Holmes-Farley Verified Community Expert]

To help you understand, nitrate and nitrite contain oxygen and nitrogen elements, phosphate contains negatively charged ions phosphorus, oxygen and at least one of them being hydrogen. So since they have very similar elements, the short answer is no, however commonly you'll find nitrate in your tank when phosphate is present. You may not be able to test for it as the nitrate may be hiding in algae, corals, or even in the phosphate itself.

Good rule of thumb is to have zero of both lol. No two tank is alike!

I'm sorry, but that explanation doesn't really make sense, and some of it is wrong.

 

[DannyB]

If you use something like GFO or aluminum oxide, no nitrate is necessary at all for phosphate reduction.

If you use something like growing macroalgae or bacteria (when organic carbon dosing) or simple growth of tank organisms, then yes, some nitrate is needed for these organisms to grow. More, in fact, than phosphate.

Organic carbon dosing (like zeovit, vodka, vinegar, etc.) is actually overbalanced toward too much nitrate reduction relative to phosphate (compared to foods) and often result in left over phosphate that remains even if nitrate is driven down very low. To get around this, you can use a phosphate export method like GFO that uses no nitrate, or you can add nitrate and allow a mixed method to export more of both.

So with using zeovit, is GFO what you would recommend to reduce the phosphate? Or would you recommend dosing nitrate? Or something else?

I know <0.03ppm is what is usually recommended for phosphate, how low should i try to get it?

 

[Randy Holmes-Farley Verified Community Expert]

So with using zeovit, is GFO what you would recommend to reduce the phosphate? Or would you recommend dosing nitrate? Or something else?

I know <0.03ppm is what is usually recommended for phosphate, how low should i try to get it?

Unless there is an algae problem, 0.02 ppm phosphate seems a good point for most reef tanks.

Whether you choose a binder or nitrate dosing is really up to you. Both can work, as long as nitrate is presently limiting the phosphate reduction. Organic carbon dosing is inherently poor at phosphate reduction so you might find that even with nitrate dosing you cannot keep phosphate where you want it. In that case, a binder such as GFO, lanthanum or aluminum oxide may be the next option.

 

[DannyB]

Unless there is an algae problem, 0.02 ppm phosphate seems a good point for most reef tanks.

Whether you choose a binder or nitrate dosing is really up to you. Both can work, as long as nitrate is presently limiting the phosphate reduction. Organic carbon dosing is inherently poor at phosphate reduction so you might find that even with nitrate dosing you cannot keep phosphate where you want it. In that case, a binder such as GFO, lanthanum or aluminum oxide may be the next option.

I appreciate you answering my questions.

How likely is it that 0.033ppm phosphate is the reason i am having an issue with cyano?

I have never used GFO, lanthanum or aluminum oxide. What would be the best option for lowering phosphate by 0.01 in a 55g? Nitrate dosing seems like it could really backfire and make things worse so probably won't go that route.

Sorry for all the questions.

 

[Randy Holmes-Farley Verified Community Expert]

It is certainly plenty of phosphate for cyano, assuming its other needs are being met.

 

[Randy Holmes-Farley Verified Community Expert]

I'd try a small amount of GFO or aluminum oxide (well rinsed) and see what that does.

 

[DannyB]

It is certainly plenty of phosphate for cyano, assuming its other needs are being met.

Sorry if this is a stupid question, What other needs does cyano have? Just want to make sure and cover all my bases.

I'd try a small amount of GFO or aluminum oxide (well rinsed) and see what that does.

I will definitely give this a try.

 

[Randy Holmes-Farley Verified Community Expert]

Sorry if this is a stupid question, What other needs does cyano have? Just want to make sure and cover all my bases.

Light, space to grow on, various trace elements such as iron, copper, manganese, etc., organics may be consumed by some species, and they may benefit from a source of nitrogen (e.g., nitrate or ammonia) although some species may also be able to get nitrogen from N2 in the air/water (unlike any green algae).

 

[Newb73]

When i switched to HW marinemix i started get some cyano.

Thats with zero phosohates on a hanna. Phospates are better controlled in my tank than nitrates (i have lots of fish) but i suspect the added vitamins and amino acids supposedly in HW is fueling it.

Im considering switching to red sea pro but im hesitant since my corals are so happy.

 

[Randy Holmes-Farley Verified Community Expert]

When i switched to HW marinemix i started get some cyano.

Thats with zero phosohates on a hanna. Phospates are better controlled in my tank than nitrates (i have lots of fish) but i suspect the added vitamins and amino acids supposedly in HW is fueling it.

Im considering switching to red sea pro but im hesitant since my corals are so happy.

As long as the other tank inhabitants seem happy, the drawback to cyano is primarily whether it bothers you. If not, I wouldn't worry about it.