Recently I used HI713 reagent (from @jonmos75) to compare phosphate levels (same water) on both HI713 & HI93713 meters and results were identical (0.04) This week I purchased 100 HI93713 reagents and tested in the HI93713 meter and the phos was 0.06. Just to be sure I used a remaining HI713 reagent in my HI93713 meter to compare and the phos was 0.03. Hanna claims the reagents can be swapped. For me the same reagent in different meters read the same and now different reagents in the same meter read different. Should I trust the HI93713 reagent in the HI93713 meter or the HI713 reagent in the HI93713 meter?