I started mt first indoor hydro dwc in an 18 gal. tote and ended up switching to 5 gal buckets,mine are stand alone buckets for now but my next set up will be a rdwc,Im going to use an 18 gal tote and 6 buckets. Im going to connect the buckets togeather with 1/2" tubeing and rubber gromets,in the res I will have a 400gph pump hooked to the tubeing,the only thing Im not sure on is how long to let the pump run,I think if the pump were to run all the time it would slowly raise the water temp,my plants are in there 7th week actually 3 days from 8 wks.so as I typed this post I have decided to set the system up now and run it with just h2o for a while and see what it does,my buckets are on a concrete floor and stay cool but Im worried the pump will warm the water. well of the to basement to set it up.I will post my findings. good luck