Carbon VS GFO?

[The Aquatic Arsenal]

People have noticed that when Phosphates and Nitrates bottom out, then coral start to bleach and go down hill.

 

[jordan10]

I have been dealing with high p04 so I bought the BRS GFO and carbon reactor. And p04 is back down to 0.03 water is nice and clear. So I recommend getting a reactor.

 

[ReefReadyYouTube]

I personally would dose up my nitrates to around 10-15ppm... and watch your po4 slowly reduce naturally! You don't want that no3/po4 disparity of 0/0.2ppm. GFO will drop that po4 to zero and then you are risking dinos occurring.

This says < 1ppm. But you say 10-15ppm so I’m confused.

 

[Idoc]

This says < 1ppm. But you say 10-15ppm so I’m confused.

It really depends what you are attempting to keep in your tank. LPS & Soft coarals typically like a little higher (dirty) parameters, SPS like lower parameters for No3/Po4. Most corals will adapt to your parameters as long as you are able to keep them somewhat stable. But, your tank is sitting with zero nitrates and high phosphates...that combination tends to lead to problems when you try to quickly drop your p04 (ie: with GFO). An elevated No3 will help to reduce your phosphates in a more natural way...I'm not exactly sure that mechanism right now, but it seems to work. After you get the Po4 down, then I'd shoot to keep nitrates between 5-10ppm.