I was having problems with diatoms in my new aquarium (waterbed 60.2) I cycled in June. Phosphate has been staying around 0.25 ppm or slightly higher with API test kit. I did a 25% water change this past Saturday and added a reactor in the sump with carbon ROX 0.8 and standard GFO mixed together with the amount recommended on the BRS calculator. I also started using a NYOS phosphate test kit I got today and the reading was 0.0 ppm. I only have 7 fish, 2 stars, 2 shrimp and several crabs. I know that some phosphate is needed for coral but wasn't sure in my situation. After 3 days the reactor dropped it that low so should I remove the GFO and just run carbon?? I do love the fact that my water is crystal clear from the carbon. I need advise because i have never used GFO before and wasn't sure how often to use it or should it be continuous in smaller amounts, etc??? Thanks in advance.