Dwc questions

How many plants per gallon of water, how often should i change the water, and what kind of nutes should i use

depends on the resevoir i fill my resevoir about one inch from top and i like flora series for nutes easy stuff to use

any ideas on the amount of water per plant

If you're using a tub, just keep the water level about 1/4 inch from the bottoms of your net pots. The bubbles from the airstones breaking on the surface is all the moisture you need in DWC. As the roots grow, they will hang down into the water and feed themselves. So ... it really doesn't matter "how many plants per gallon." Of course, the smaller the tub, the more maintenance its going to need.

Vi

well a good rule of thumb that i learned is 4.5 to 6 gal per plant so like if i had a 20 gallon container i'd only put at the most 4 maybe 5 if your gonna scrog or something but they will be really close together and screw with the light getting to all the plants