The water has high magnesium and calcium. Are the valve ceramic?
Researching shower/faucets it is indicated that the ceramic disc valves are the best choice to hold up against magnesium and calcium in the water; scaling. Is this valve ceramic, or what valve to you have that is ceramic?
I have not purchased; still shopping. Delta is at the top of my list.
Thank you for your question. Delta Faucet model # RP50366 is a screwdriver stop used on our valves so the user can turn the water on and off at the valve instead of turning off the water in the whole house to service the valve.
We do offer ceramic cartridges for our 1300/1400 tub and shower series models. RP74236 is the model for the ceramic cartridge.
Date published: 2019-01-20