We've had the pool open for about two weeks and have had a continual brown dust problem gathering in the bottom of the pool. Test results are:
pH = 7.6
CYA = 40
Alkalinity = 90
CH = 170
I've read a lot of the old posts with this problem and it seems to fit the same pattern as others. Only happens when the pump is running. Can pass an OCLT at SLAM levels, etc.
Today I pulled out the stairs from the pool and found the previous owner had weighed it down with a couple of broken up cinder blocks and one round piece of cement. The inside of the stairs was extreme filth and smelled really bad. Pictures are below. I vacuumed the mess out of the pool that got released when I pulled the stairs out, backwashed the filter and SLAMed to 18 ppm. Some more of the dust has accumulated since the slam, I brushed it and it later settled again, but it is still brown. I thought at this chlorine level, it would turn white. Should it not?
My main question is about the stairs. I assume he had the cinder blocks in to keep the stairs stable. Is this a typical type stair or is there something better? This thing is always going to have a dead space with uncirculated water trapped in it. The stairs have two handholds for lifting it on each side which may let some water flow through it with the circulation pattern in the pool. This may be where the dust has been coming from as what got unleashed getting the stairs out behaves like what I have been seeing.