Nitrate stuck at 5ppm

Clownfishy · Nov 5, 2017

Using Redseas N03-P04-X I can get my Nitrate down to 5ppm using 3ml a day in a 200 litre aquarium. If I use 1ml more, my aquarium gets covered in a white jelly like substance. My phosphate level has always read 0 but I believe the little algae I have is taking it up.
My question is, does having low levels of phosphate prevent the reduction of Nitrate? I just can't seem to get the level down below 5ppm even with 10% a week water changes over several months.

SouL_Shaker · Nov 5, 2017

Clownfishy said:
Using Redseas N03-P04-X I can get my Nitrate down to 5ppm using 3ml a day in a 200 litre aquarium. If I use 1ml more, my aquarium gets covered in a white jelly like substance. My phosphate level has always read 0 but I believe the little algae I have is taking it up.
My question is, does having low levels of phosphate prevent the reduction of Nitrate? I just can't seem to get the level down below 5ppm even with 10% a week water changes over several months.

If no3 goes up po4 goes down. If po4 goes up no3 goes down.

SashimiTurtle · Nov 5, 2017

Why do you want your nitrates lower than 5ppm?

DarkSky · Nov 5, 2017

5-10ppm is ideal. Don't try getting it lower. The white goop is most likely a bacteria bloom from carbon dosing.

To answer your question, yes, if you're deficient in one of the big three nutrient sources (carbon, phosphate, nitrate) you won't be able to lower the other two via bacteria. The stuff you're dosing is a carbon source which allows bacteria to reproduce, most of our aquariums are carbon limited so bacteria won't be able to consume your phosphate and nitrates via reproduction.

SouL_Shaker · Nov 5, 2017

I keep no3 at 7ppm and po4 at 0.05 ppm. The less amount is risky.

Clownfishy · Nov 5, 2017

Sounds like I am worrying about nothing, I was aiming for Nitrates to be around 1-2ppm but i think I will keep them where they are then!

Thanks for your help

Randy Holmes-Farley · Nov 5, 2017

It may be that very low phosphate is keeping the nitrate from going lower, but I would not assume that is the case. The fact that bacteria become visible with a higher dose of the NOPOX does not mean that a higher dose isn't needed to reduce nitrate further.

That said, I agree that 5 ppm is fine for many reef tanks, unless your goal is a ULNS tank or you are trying to beat back an algae problem with low nutrients..

Clownfishy · Nov 5, 2017

I do have algae or should I say pockets of hair algae which I cannot seem to get rid of. Is it OK to allow the bacteria to cover the glass and just scrape it off and is it doing any harm? If so I would like to increase another 1ml to see if the Nitrate drops 1-2ppm but was worried about the amount of white bacteria and slime appearing.
Many thanks