Ok....but I honestly wouldnt use any with your tap water....you don't need one single extra ppm on board.
Weedhound Reviewed by Weedhound on . advice please Lets get to the details for veg 3 100w CFL's running 6500k 1 small 6inch fan DWC system with 15 sites Milwaukee 3-1 ph/ec/tds meter 2 and 1/2 gal of RO water 2 6'inch airstones Rockwool cubes net baskett Rating: 5