Thank you for the input I test w/ Hannah Low Range Meter, agreed Checkers are junk. . I thoroughly clean vials in alcohol and store clean and dry in a dedicated plastic container. My testing procedure has remained consistent for more than 6yrs w/ repeatable results (I always run 2 different samples). No change in feedings or dosing, the only change was the recent nasty colored cold water which i believe shot my RO/DI PO4 from .00 to .08 and PPM from 0 up to 8ppm (keep in mind the values have been stable over 2 yrs) that being said my primary concern is not the presence of PO4 or precise value but the huge rapid jump in PO4 levels
I did not know the Nom vs Absol ratings for the filter cartridges! Can you recommend a good supplier? This may explain why this batch of filters did not last long (4-6wks)