I've got a 50G cube that I've been running for about 7 months and have began battling some cyanobacteria in a corner of the tank. Fishload is a clownfish pair (with a leopard wrasse and yellow assessor coming from QT in a week or so). Corals are a hammer, couple of acros, rose stylo, turbinaria, superman monti and grafted monti cap. Also have a small island of zoas on a rock on teh sandbed. All are small frags added within the last few months. My parameters as of yesterday are as follows: Salinity- 1.025 PH- 8.1-8.3 ALK- 9 dkh CA- 450ppm (Red Sea Calcium Pro) N03- 2.0 (Red Sea Nitrate Pro) P04- 0.0 (Hanna Low Range) My issue is, I've got a BRS media reactor that I ran GFO and carbon (ROX) in a couple of months ago. I had several corals bleach out and actually lost a couple. Since taking GFO and carbon offline, as well as letting my nitrate rise gradually from .25 up to 2.0 over the last month or so, I've seen coral health and color return. Seemed the more I fed, the happier the corals got. So, I attributed the issues I was experiencing to my having stripped the water of nutrients. Now, event though I'm reading zero phosphate, I'm seeing cyano. Corals all look as happy as they've been since they were added. So I'm assuming that there are phosphates in the water that the cyano is utilizing before I see them on the tests. I'm inclined to restart the GFO (and possibly carbon) but don't want to repeat the issues I had in the past. If I start feeding less in an effort to reduce nitrate, I'm also afraid that corals will begin to suffer. Since the tank is still fairly young, I'm wondering whether the cyano issue is simply a later stage of tank establishment and will run its course. On the other hand, I want to get ahead of any problems that are percolating. Any suggestions on how to proceed? Many thanks.