The first problem was using thread together fittings. The manifold fittings cost a little more up front, but they are well worth it. You can take them apart and build something different if you want later. With 3" plumbing, most of the time when you take something apart, you will never get it to seal again without replacing the male side with a new piece. The fittings you do have to screw together, use Rector Seal only. Put it on both the male and female threads as mentioned. It seems the pros here bounce back and forth between the baby blue and black stuff. My brother has insisted on buying the chunky yellow stuff against their advise although we haven't had any trouble with leaks once we got to the point where we only use threaded fittings going into tanks and pumps and use manifold fittings everywhere else.