It's 4 ML/Liter (a little over 1 quart) of both the Grow and the Bloom solutions. I ame 5 gallons in another bucket, fill to my net basket height I want and save the rest (covered) to add. You have to be careful as the water precipitates or is respired by the plant while the salts stay and become more concentrated. Here's your frequent meter checks! Buy them first I swear to God. Fuck those drop test kits with color change. I use one but JUST to be sure I'm close before using the meter (tips wear, have to stay wet in saline solutions). After that prelim check (which I'm sure I'll ditch with experience) it's meters ONLY!