Thanks in advance. Lots of valueable information on these forums. I'm looking for low cost ideas for a diy waste tank. I'm planning running 4 3stage vac motors. Several guys on here have mentioned using a small waste tank with an auto pump out to a poly drum. With this setup I wonder if I'd run into sucking water into the vacs with that much suction and such a small tank? (20 to 30 gallon). Someone posted an idea about using a 22 gallon sump pump basin from homedepot. Also I know that a metal drum will buckle on its own, but I wonder if I was to weld brace supports inside/outside the drum if that would be sufficient. Anyone have experience with this idea?