Since I added a chlorinator to my pool I also installed a 2" in-line check valve as recommmended. I have had to replace the Flapper assembly two times in two years because the small metal spring breaks. I replaced it earlier this season and I noticed today the spring appears to be broken again, because the valve flapper was open when the pump was off. Can I get a better or stronger spring for this? Im sure others are having the same problem.