quick DWC question

does anyone have any insight on whether I can use a 32 or 40 gallon tub for a 10 site AUTOFLOWER DWC?

if so, what kind of pump can someone suggest for like 5-7 12 inch airstones?

40 gals or more depending on what size plants under wat light
look into electromagnetic pumps they come in different pumping power. get the one than can easily operate wat airstones you want

I ran a deep water culture set up before. Are you top feeding or running it as a circling nutrient that connects the bottom of the buckets? I have lots of pics of my set up to help show you. Zem is right about the pump!! Its not going to be cheap and you do need a EM pump. Sounds like you have 5-7 12 inch air stones so their for you have a 5-7 DWC set up. I did mine in 5 gallon buckets with a 40 gallon res. And than I had a 5 gallon bucket the was controlled by a float valve for toping the res off with fresh water. The 5 gallon bucket that had fresh water had to be elevated above the res, again controlled by the float valve.