I've a new account, but have been following the site and process for a couple of years. This summer, I've hit one of those.....odd kind of issues.
I'm using bleach, occasional dry acid to keep the ph down, occasional chlorine tables in a chlorinator to keep the CYA up. I've SLAMed the pool twice so far this summer.
The problem is that get this very fine yellow greenish powder on the bottom of the pool. It accumulates in obviously visible quantities in 2-3 days after brushing. IT doesn't clump at all, but is a perfectly fine light powder which wipes off with a hand when you lightly touch it, and dissolves immediately in the water. It also it fine enough to make it through my pool vac cloth mesh bag. Mostly on the bottom with occasional bits on the sides.
The odd part is that there is a slight drip occasionally coming off my pressure gauge which has left a bright yellow dry residue trail down the side of my sand filter.
Calcium 170 (I need to add a bit more. Any chance this is the culprit?)
The water is a bit cloudy and has a slightly yellow/green tinge.
Also, the pool gets full sun and the powder/algae distribution doesn't seem to care much.