My pool is built in such a way that the filter is located below the waterline. When I blow out the line and close the valve at winter closing. The valve leaks over the course of the winter and as a result it cracks the valve as the water seeks its own level. I noticed the plastic ball valves fail and cause me issues. I am considering a brass valve for the deep end and was wondering what the water chemistry would have on valve. Would Chlorine destroy the valve. Any suggestions on how to fix permanently.