Ok all you stick fans......what do you use to test your phosphate ? I used a hanna 713 , elos and a salifort ...they all come up with different readings......the hanna i did 3 times in a row and came up with 3 different readings i got .09 ppm, .34 ppm and .03 ppm......which do you go by.....thinking about trying a hanna 736 which reads in ppb which is suppost to be more accurate.....what does everyone else think ? ....need some input