We are having our pool heater installed this next week and a question has come up. Right now our filter system is just hooked up with the flexible hose that came with the pool set-up. A plumber I talked to about doing this work for us said that we now need to switch everything over to PVC pipe in order to add the heater. Is that so? I hate to see this turn into any bigger of a project than it has to be. Its a Hayward H-100 natural gas heater.