I use gh nutrients and i grow in 5 gallon buckets. as long as you wait until the soil is dry to water, you can water as much as you want in one sitting. I water 2 gallons every 4-5 days. In veg and early flower i was watering 2 gallons per plant every 5 days, but as i got later into flower i noticed the soil drying out faster, so I switched to every 4 days and everything seems to be going well. They say you want about 30% run off when watering, so you kinda gotta figure out how much you need to get about that much runoff. As far as mixing the fox farm nutes...i am not entirely sure, but how it goes for me.....there are 2 different nutes i use, flora micro and flora bloom.
1. I take my gallon of water and my measuring cup...measure out 8ml of flora micro then dump it into the gallon of water. Shake.
2. Clean measuring cup...fill 16ml of flora bloom then dump into water and shake.
3. Adjust pH to around 6.5 (for soil)
Done. I do this 2 times for 2 different gallons of water for each plant. Get it? I had trouble figuring out nutes at first too, but it is really that simple.
Dont mix nutrients in concentrated form. Pour one into the gallon, shake it, then the next, shake, then the next. All in the same gallon, just not at the same exact time.
Hope this helps.
As long as you wait for the soil to dry out before you water again...you wont be overwatering. regardless of how much you water in one sitting. Im pretty sure thats correct.