Hmm that’s very interesting. Let us know how it goesIm dealing with same issue and will try the following experiment. I tested both my phos and nitrate a couple of days ago...they are in a good range
Phos: .12*
Nitrate: 8ppm
I have an asterisk next to the phos, because my levels are normally .04 - .08...
I noticed if I blow off the cyano, and/or stir the sand bed and test in a few hours, my phos jumps.
Today before the lights came on, i stirred the sand bed and blew most of the cyano off my rocks and tested a few hours later.... result: .25!
I believe the cyano is binding the phosphate and my activities are causing the cyano to release phos? My next move is to add phosgaurd to rapidly take the phosphate out of the water so the cyano cannot use it to repopulate my tank...
Thats the thought anyway.