Have you had any luck, Pat? I have the same problem, although maybe not as bad as you. Tan stains and roughness. I have a mesh cover too.

This is my second opening. The first closing was right after completion of the build, so I think my plaster has still been curing and causing my PH to get high very fast after closing. Both years my PH was sky high upon opening and my hardness and alk were both low.

Tomorrow I'll try dropping the PH and giving it a good brushing.