Guys,
Kind of a different topic, but, just picked up the Phosphorous Ultra Low checker(736 reagent), I have the phosphate low (713 reagent) as well. The low worked great from .1 to .25 but, once I got Phosphate below .1 I could do the test 3 times at the same time and get 3 different numbers from .03 to .09. I was told bad reagent batches so I bought different batches, same result. I spoke with Mario at Aquatica he suggested this Phosphorous checker in ppb, the formula to convert to phosphate is Phosphorous PPB x 3.066 / 1000. Same day tests are 27, 28, 29 worst case, often 27,28,27 since this is in PPB actual result is .08278 (27) to .08891 or .006 PPM difference. Since the reagents (713) are $10 for 25 and the Phosphorous with 8 tests is $50, I figured I'd give it a try. Glad I did, way, way more accurate. Again, if your tests are over .10 it matters less and .25 even less, but, if you are shooting for low phosphate measurement like most Hanna guys are, the Phosphorous PPB is the way to go.
