Joe D posted an awesome document explaining how to properly mix the Tower Garden nutrients (document called Mixing TG Nutrient Solution), but I'm still a bit confused. I followed his directions step by step to fill the entire 20 gallon tub. All seems fine there. I get confused when I'm trying to have the proper mixture ready in a 5 gallon bucket (as suggested) so as to replenish the Tower. The directions say to substitute the word "tub" for "5 gallon bucket." If I substitute those words it appears I'm putting the full 400 ml of each in the 5 gallon bucket and filling the rest with water. That seems to be double the strength of the 20 gallon tub. (I did that and PH is way off- 4.5) Should I be waiting until there is only about 5 gallons left in the tub, then add the mixture in the 5 gallon bucket, topping the rest of the tub with water (therefore tremendously diluting the mixture)? Or am I way off here? Logically it's not making since to me, so I think I must be missing something! Thanks for your help.