I've got a customer with a ~30k gallon indoor pool. A few details:
The pool runs 24/7. It has an Aquapure that even at 1% production puts FC around 10ppm within two weeks. It has a Delzone CD ozonator running 24/7. pH consistently creeps up (even with SWG off) and requires about 1 gallon of acid a week with TA maintained between 80-100. It is a relatively new (less than 3 years) plaster pool. Calcium Hardness is somewhere between 350-400 depending on the day, CYA is 30-40.
Because of the indoor installation the room is equipped with a Dectron dehumidifier. It maintains the room at 80-82 degrees, the pool is kept at 84. Humidity is around 40%.
The tile and deck are unfinished slate, the walls are stone (not sure what type) and glass, and the ceiling is vaulted with douglas fir decking.
Since the scumline is unfinished there has been scaling there from the get go, but recently the customer began to notice a buildup on the decking up above. They had it tested for mold and it was negative. It is most concentrated about 3 feet above the eave. They also discovered that the home builder's insulation job was lacking, and that there was little or no insulation at the eave. In some spots you could put a wire straight through from inside to out.
Seems to me that the cold air coming in at the eave is creating condensation on the decking which is evaporating and leaving the spots. I'm wondering if any of you with more indoor experience have seen anything similar, what the issues were, and what can be done with the pool to help reduce it (bringing the water temp down is probably not an option). Like I said, I think this is inherently an issue with the room's insulation, but I want to be sure I've done everything (or at least offered) that might help the situation.