OK, so I went to the LFS today to try and get to the bottom of this. They had done a phosphate check earlier and was. 07. They used my reagent and machine and came up with. 07. I'm convinced. No phosphates. But then again I do have some spots of cyano I'm fighting with. Also using phosguard. Oh, and mine is a low range. Not ultra low range. I'll keep my eye out for the ulr. Thanks for the responses folks.