I have been fighting this abundance of algae for over a month and change now. I had a lot of leaves fall into the pool over the winter and dissolve due to the warmer weather and created a big mess for me in the spring. I tried to clean it but the water I started with was brown and it took a significant amount of effort to pump all that brown sludge from the leaves out.
But now I have a different problem. Dead/alive algae. I tried shocking, adding algaecide, shocking and shocking some more. The water is green no matter what I do. If I add some floc, i can see the clearer water on the surface but as soon as I run the vacuum to vacuum to waste, the whole pool is back to green and it won't go on the bottom until I floc it again, which is getting rather expensive.
But my question is not really about getting the algae killed as I understand the shocking/vacuum to waste mechanism, but rather I have a feeling it has to do with my filter. Anything that remains in the water that does not settle on the bottom is not filtered out. I tried vacuuming to filter all the sludge on the bottom just to see how it responds and all of it was coming back through the returns back into the pool. Almost like nothing was getting filtered.
The filter I have is a Hayward S220T Pro-Series 22-Inch 1-1/2-Inch Vari-Flo Valve Top-Mount Pool Sand Filter. I installed it myself 3 years ago and added 3 bags of ZeoSand ZEOSAND 25 Pool Filter Sand Alternative, 50-Pound. Technically this should be enough but it seems that the filter is ineffective. I even tried adding some DE into the skimmer to no avail. Is my only option to get rid of the dead algae sludge vacuuming to waste or should the filter work with enough backwash/rinse cycles?