I have 8×30 pool and so frustrated see orange "sand alike algae" on bottom in my pool. I have all 3 chemical regularly :sanitizer, shock and super algae.. even test it all levels are good. I keep tarp cover when not in use. I have vacuum done but seems come back each morning. help what do stop it keep coming back.
It is possible that you have one of two problems. 1) you may have a dead area where there is no circulation and therefore chlorine is not reaching this spot and algae is starting there and spreading even into treated areas. Or 2) you have holdover algae somewhere else. Could be that it is resident in a dirty filter or that there is a porous area of your pool that would require scrubbing to remove the entrenched algae. The filter could also be letting sand and other contaminants back into the pool if there is a leak or damage to the filter.