I have had issues with my two shower heads in my master bath since buying my unit last November. The shower has two shower heads. We have soaked the heads, etc. Most recently, I had a professional plumber come out and he ordered, flushed, and replaced the cartridges (inside the handles) and I bought new expensive shower heads. I took my first awesome shower in almost a year. My daughter then took one 3 hours later and one shower head did not work. When the head was removed, there was no issue with the water flow and a lot of white, gooey sediment in the trap screen. Where does this come from? The plumber now is having a water heater guy come out to look at our 2011 water heater and thinking maybe its the cold water dip thingy (at this point I didn't understand anything he said). This is a big problem and don't know who or how it can be solved. I really appreciate any help I can get.