All last summer, (and even throught the winter) I had a fine, tan colored, dust like, residue that would accumulate on the bottom of my pool and on the steps. It vaccums up, when you brush - it clouds the immediate area and is very difficult to sweep.
I poured enough clorox in my pool last year as recommended, to start a laundry (lol). It never affected this residue. It is not visible on the side walls - just the bottom.
That being said, I live in a very rural setting, with a field 100 yards away. Is this dust, algae, or pollen. All last spring I fought daily to clear the water - kept my levels way up (to the point I was afraid I was damaging the liner), washed the filter sand, changed filters, services the salt generater - only to finally realize it was not algae, but North Carolina Pine pollen. In April, the pine pollen in this area is so thick for 2-3 weeks, that cars, houses, every thing turns yellow.
SO..... this year, I'm going to cover the pool, diagnose this powder on the bottom, then purchase a solar blanket. Any recommendations on testing, treatmentment, and a solar blanket?