Has anyone experienced this: Ph will not go down lower than 8.0 TA is at 100. 2500gal indoor spa. I have replaced the heating element 3 times in the last 3months on the RAypac 11kw. By the looks of the debris in the water the element is actually disintegrating. I suspect that in my efforts to bring down the PH I have inadvertently damaged the heating element. Thoughts?