I have an older pool with an Aquatech Filtering system. I believe this system was supplied to Aquatech by a firm named Pac Fab Inc. Sanford, N.C. I am in need of filters for this system and best that I can gather is info on located on the filter housing. It states that the Model # is FSH/SH 500. The design flow is GPM 500 and the replacement Cartridge is Part # 17-4849. Can you help me locate these cartridge filters? Joseph S Diaz josephstevendiaz@gmail.com