Originally Posted by thumpertom
Thanks ddcar, I already have that setup. I was just trying to figure out how to drain all of the tanks from one connection thus simplifying the process another step beyond what I have now.
Not that hard to do, just get an 1-3/8" hole saw, mark where you want the hole and drill it and then hand file or rotary grind to get a tight fit. Use ABS primer & glue and glue it in. Just to make sure, I also used silicone caulk around the connection and it's held now for 3 years. You do have to add another shutoff valve to the 1-1/2" line to keep the 3 tanks separated.