Hi! I need advise about The Ultimate GH Booster from greenleafaquariums.com ( http://greenleafaquariums.com/aquarium-fertilizers-supplements/gh-booster.html). Did somebody used this product? How much I have to dose for 90 g aquariums? I'll start to use Co2 and wonna be sure than my PH not gonna fall down. What else you use to prevent it? Thank you