Glacier Bay from HD, we have 2, seldom have any problems, they have a straight through shot that seems to help. The seat that comes with the "kit" is not too good, but works. As for the possibility of problems further down the line, use septic tank stuff, even if you are on a regular sewer, be aware that bleach will kill the enzymes and bacteria, though. And maybe you have roots in the line--copper sulfate.