I have been getting rust spots on the bottom of my pool under the inlets. I suspect that it is coming from the heating tubes (it is the only steel that I can find in the system). I get a loud knocking sound from the heater when the system is on. I replaced the ESC temperature control board last year. What do I need to order to replace the heating tubes? Or due to the age of the system should I look into replacing the entire heater?
thanks for your help.
thanks for your help.