Great Nitrates, high phosphates, using Nopox

[IndyReef78]

Here are my most recent parameters:

Alkalinity 8.2
Nitrates 10-15
Phosphates .307 on Hanna ULR
Calcium 500
Magnesium 1500

I have been using NoPox since around April when both nitrates and phosphates were sky high. Got the phosphates down fairly easily and they had been down for quite a while. Finally got the nitrates down with NoPox and both SPS and LPS have been doing well. Now all of a sudden, I’m getting a bunch of brown fuzzy algae on my rocks and back of tank and my phosphates are out of control again. What can I do to bring them down without screwing everything else up and while still dosing NoPox?

 

[Randy Holmes-Farley Verified Community Expert]

Organic carbon dosing like NOPOX generally does what you see, and you may need to use export methods like GFO if you want to bring down phosphate while using organic carbon dosing. The reason is that organics can drive denitrification, a process that lowers nitrate but leaves phosphate basically unchanged.

 

[IndyReef78]

So it’s ok to use GFO along with NoPox? I thought I shouldn’t do that. I have some, so that would be easy enough....

 

[Randy Holmes-Farley Verified Community Expert]

So it’s ok to use GFO along with NoPox? I thought I shouldn’t do that. I have some, so that would be easy enough....

Certainly they can be used together. Many folks do. I used organic carbon dosing (vinegar) and GFO together for years. You just need to be sure you do not drive phosphate (or nitrate) too low.

 

[csb123]

I’ve used GFO while using NOPOX, with not problems.
I like using lanathum to lower phosphates.