Phosphate experts

[Seth401]

So about a month ago I got a nice bloom or green algae and cyano. On 736 Hanna my phosphates were reading in the .05 range. Glass was also getting covered much quicker than usual, like have to wipe it everyday or there's a very noticeable green film. Most of my sps look great buy growth on 90% has slowed, and a few have browned out. I started running small amounts of phosfiltrum gfo. The situation has improved some but I'm reading 0 everytime on my Hanna 736 but the algae is still growing on the glass daily. Is this the algae masking a phosphate problem? Should I continue to run gfo? Ive been so busy at work I haven't been able to do a good water change in two weeks. Should I change a good 20%? It's frustrating we spend this money on test kits but if you have algae growing you can't get a good reading!! Thoughts? By the way I dose potassium nitrate to keep them between 2.5-5

 

[CoralNerd]

Man, I would hold off on potassium nitrate (P.N.). Do you run a fuge and grow macroalgae? Only reason I ask this is your title reads phosphate pros.
I'm not sure how advance you're, and P.N. could be a slippery road. Especially if your out of town and not monitoring your tank.