Not sure if it is new model or not, how can I tell? For me the regents dissolve OK but it take some time to shake, there is absolutely no way to dissolve regents in the given time window (30 second?), I always use the two tubes and start the test after I have two tubes ready, one with water sample & other with dissolved regents. I will prob. bug hanner to get some new regents to check out, what should I say? The regents are hard to dissolve? Definitely! I take N & P reading as indicator of balance of nutrient import and export, as Rich mentioned what important is trend, not specific numbers. I mainly test N as gauge of nutrient & don't test P often, the recent test I wanted to see what is impact from carbon dosing, I kind of expect lower reading since the carbon dosing bring my N from 5 - 10 to less than 1. From what I read cyanbacteria is combo of bacteria & algae, they feed on multiple sources, they take P but not as dependent on it like algae. So what would be other options to beat it other than manual remove? My cyano problem mainly on sand bed since I have sugar grain can not blow with too much flow.