15k gallon in-ground pool, SoCal, with a SWG that had been malfunctioning, but I just put a new salt cell in there today so in theory it will be helping with chlorine from here on out.
I accidentally let the chlorine get to zero a month ago, and saw orange algae growing on the side of the pool. I treated it using the TFP recommendations, elevating the chlorine to shock levels via liquid chlorine, brushing multiple times daily, vacuuming, etc. Then I performed the OCLT and thought I had passed. So I put my solar cover back on the pool and assumed I'd let it drift back down to regular levels. The solar cover, in addition to warming the pool, also seems to preserve FC -- FC drifts down a lot slower with the solar cover on than without it.
1.5 weeks later (i.e. today) I took the solar cover off to do the weekly vacuuming, and I spotted more algae. What gives?
I checked the stats today:
I have three ideas I'd like to run by the TFP gang:
1) Is it possible the solar cover had anything to do with it? Can the solar cover hold on to algae? If so, then I inadvertently cleaned the pool and then trapped algae in there. How do I get algae off the solar cover??? (It is VERY difficult to rinse due to its size and the size of my yard.) Or is it sufficient to re-shock the pool leaving the solar cover off? (Will algae continue to live on the rolled-up solar cover sitting on my driveway?)
2) My phosphates have always been high in this pool and they always drift upwards over time. It's been years since I treated them. I have some phosphate remover...should I just use that to remove more algae food from the pool? (Note: unfortunately the phosphate remover directions say to wait until FC is 1-4...which means I'd paradoxically have to leave the algae untreated for a few days until the FC goes down, THEN apply phosphate remover, then, I assume, shock the pool again.)
3) After the algae outbreak 1.5 weeks ago, I didn't clean the filter. Should I have? If so, how long after? I did look at the pressure gauge and it rose by a tiny amount after the algae cleanup, but nowhere near the 10 points that I normally wait before cleaning the filter.
Any thoughts on either of these two, or other things I should think about?