Low phosphate and High nitrates

[duncantse]

Hey can someone come up with a game plan on what I can do at this point.

- 2 year old 40 gallon mixed reef running a reef octopus protein skimmer as the only filtration and 10% waterchange weekly
- 5 fish total
- was at 0.06 PO4 and 5ppm NO3
- mindlessly ran gfo in a reactor and PO4 would constantly be 0 so I upped my feeding by a lot feeding reef roids, pellets, and frozen daily
- was sitting at 0 PO4 and 25pm NO3 so I ended up stopping gfo
- currently at 0.06 PO4 and 25ppm NO3

What are some options in my situation to lower NO3?

[Vinny Kreyling]

Nitrates can be 10 or under, BUT NOT-0- & Phosphate should NOT be -0-.
As long as the corals are growing just do your water changes.
That 20,000 gallon reef runs 0.16 PO4 & looks great.
Personally I worry when I get over that # & change the GFO.

[outssider]

search "carbon dosing" (I use vodka) you can get your nitrate down as low as you want

[duncantse]

Hmm okay sounds like the 2 options for me would be to either carbon or just wait it out with weekly water changes and check if my nitrates are dropping.

Everything is doing fine so maybe I can just leave it alone if 25ppm nitrates is not an issue

A question with carbon dosing is that will it bottom out my phosphates? I heard if phosphates gets too low then that is a limiting factor and nitrates will not decrease.

[SantaMonica]

The N-limiting-P, or the P-limiting-N, is only for photosynthetic filtering (like algae), and only rarely if the filtering is high and if N or P is "zero" on a hobby test kit.

If you are using gfo or other chemical filtering, then the N or P is independent of each other.