I have the Hanna Ph/ppm/ec/celcius meter. Its the black one with the long probe thing. And I did calibrate both the ph and ppm and then checked to see if it was the same with just the ph liquid tester. I finnaly found a hydro store that will order me some Pro-mix and I was gonna transplant them into that. Hopefully that will eliminate the guesswork on adding lime. So as for flushing them, should I go with the rule of 3 times the size of the container with water ph'd to 6.3?