I have this brown dust (it disintegrates when I brush it or just come close to it with a brush) that accumulates at the bottom of my pool only while the pump is running. If I vacumm at night, then shut the pool off, I will wake up the next morning and it's ok (no dust accumulation). However if I vacuum in the morning and run the filter all day, when I come home from work, it's all over the bottom again. Been going on since I opened the pool in May.
Here are my latest readings using the TF-100 kit.
Could this be algae? My water is always crystal clear. It accumulates in any crevices and seams along the bottom only when the pump is running. I wonder if I need to change over the DE in my filter? Can't get rid of the stuff, whatever it is. In this picture you can see it at the edge of the walls and the bottom and it's scattered around the bottom. The dark spot in the upper right side of the picture is just the reflection of a tree.
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