Spot forms daily?? What to do ??? W/ pics

Hey everyone so I have replaced, filter, filter sand, pump, motor, SWG and all. All my levels looks good but I’m get this dirty spot which forms daily? What is going on? See pics
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That's like a sand drift? Or is it sticking to the plaster?

If it's dust/sand settling out, then it's just a dead spot. Try re-aiming the return jets.

If it's more like dustbunnies that go poof when you approach with a brush, that's dead algae clumping, and you need to SLAM.
 
That's like a sand drift? Or is it sticking to the plaster?

If it's dust/sand settling out, then it's just a dead spot. Try re-aiming the return jets.

If it's more like dustbunnies that go poof when you approach with a brush, that's dead algae clumping, and you need to SLAM.

I have tried to re aim, change how hard the skimmer sucks etc.... I have the jets doing a nice circle.... it’s like the exact same daily spot that forms and it does not disappear but will go away if brushed.....
it’s like a spot of dirt I have tried a slam with same after result.

I need some help
 
Looks like mustard algae.

I would suggest a full SLAM and then maintain fc at 15% to 20% of cya for a week. Thereafter, maintain the fc at 10 to 15 % of CYA for about two weeks.

What is your CYA and what do you keep the fc at?

Did you complete a full SLAM and pass all criteria?
 
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