I have a 15' Intex round pool with a sand filter.
I opened the pool last Saturday, and my filter GFI had tripped a few weeks ago, and I'd dropped the ball on chlorine levels, and it was a terrible swamp. I mean terrible: clouds of solid algae swirling.
Over the winter I use trichlor tablets just to take maintenance hassle from daily to weekly or so, and then I'll just dilute if necessary if CYA has climbed while the pool is closed for the winter. Not a big deal, water is very cheap in my area. While the pool is open in summer, I maintain it daily with bleach as per the TFP approved protocol.
When I opened the pool, CYA was about 50, which was fine, TA 90, ph 7.2. All fine.
So I started shocking up to 20 ppm and I've held it there consistently for five days now. It is now holding chlorine fairly well. 2-3 ppm loss overnight. Continuing the shock process.
The problem is that while I did go from pea soup to your basic cloudy green pool, it does not appear to be progressing any further.
I've brushed at least daily, this usually stirs up more dead algae.
I've also vacuumed a few times to waste from the bottom of the pool, which does seem to be removing dead algae from down there.
But the pool just hasn't improved much in appearance over the past several days. Filter is running 24/7, backwashing a couple times a day.
I am considering shutting off the filter overnight to promote settling and then vacuum to waste first thing in the morning. It seems the sand filter is just not very effective at removing these particles.
Does that idea have any merit?