Wow, didn't realize this was going to be such a big hit... anyway good luck you guys and have fun.
checkinhawk, I selected sch 40 PVC for a couple of reasons, first it was easier to get my hands on then acyclic, second my reactor has to hold about 60 to 70 lbs water pressure, it is in line with my RO/DI top-off system, a line comes from my RO/DI unit, into the bottom of the reactor, out the top and into a float valve in the sump, when the pressure reaches 70 lbs the RO/DI shuts off and I wasn't sure what it would take in acrylic to handle this pressure plus wasn't sure how thick the acrylic would be. The pvc is thick enough to tap and thread a valve into to keep it leak free.