I'm installing a new heater for a spa and am having trouble hooking up the plumbing. I am using 2" PVC and have built the whole manifold from the filter to the heater and to the return to the spa, but I can't figure out how to hook it up to the existing pipe that returns the hot water to the spa. It sticks up about 5" out of the cement pad where all the equipment is located, but it's not a standard size/shape. It's shaped like a car radiator's hose nipple with a bulge between two narrower bits so that you could put a hose over it and clamp it behind the bulge but i'm trying not to do it that way since the hoses that are used with PVC aren't meant for pressure or heat. That is how it was originally hooked up but when I took it apart the hose was all deteriorated on the inside. None of the exposed part is a standard size where I could just cut it and bond a coupling on. I was thinking about trying to use a radiator hose but don't know what the spa chemicals would do to it.?