Sandy, Sorry, I was trying to get some digital work done an djust used APUG as a break. I also use the RO water for 95% of my clearing bath mixing. When I was on a well in Taos, every trip to the store included a hand full of distilled water. The RO system has been great in providing good clean water.
I had two additional thoughts on the cystals that Mike was having problems with on his prints. Was that from the "hard to mix" developer? Perhaps you just didn't have your chemistry balanced and the solution that you beleived to be PO was indeed too heavy in Oxalic Acid? I have noticed over time of using it, that it has a tough time staying in solution (rather low soluability perhaps), and with the heated solution you are able to get it into solution, but after developing it, the print cools enough to allow the recrystalization of Oxalic acid?
What if you soak it in some hot distilled water?
What paper did this happen with?