I am installing a tank and sewage sump pump. Do the tank openings need to be sealed with anything more than the flexible gaskets that came with the tank?

Hi Lanny

If the lid gasket is overlapped as shown in the instructions and the gaskets installed at the pipes properly then in theory, no, you should not need to do anything else.

With that being said, I always add a bead of clear (flexible) silicone caulk around the pipe flanges and over the bolt heads for best result!

Do the instructions for your pump call for you to drill a 5/32" hole in the pipe (under lid)... check it out as it is usually required to prevent the pump system from getting air-locked... ;)

Mark