I purchased a house in November 2025 with an existing above ground pool (vinyl liner). The pool was already closed at time of purchase so I had no insight into what I was getting into. I opened the pool on Friday, May 9 to find a thick layer of algae on the bottom. I have been slamming since the pool filled on May 10. I've made some significant progress after three days of nonstop brushing and vacuuming. I finally got in the pool yesterday since the water was mostly clear to get some of the stubborn spots that wouldn't come up with the brush or the vacuum to find most of the floor felt like a fine grit sandpaper. I grabbed a kitchen sponge and used the abrasive side in a small spot just to see if I could remove the buildup and that did work. After doing some research, it seems like this is most likely calcium scaling. 
I am getting close to the end of slamming (and will start dealing with the scaling next). My CC is at 0.5 and I am no longer losing > 1.0 PPM of chlorine and the water is nearly clear. I am probably one or two good vacuums away from comfortably letting the FC drop to normal range. The problem I'm running into is that the algae has stained the scaling or maybe the scaling has trapped the algae below it (is that possible?). Am I good to stop slamming as long as there is no more loose algae in the pool or do I need to continue slamming until I can get the algae that has combined with the scaling?
And then as far as the scaling goes, I am unable to easily scrape any of it off because it is only on the floor of the pool. After I'm done slamming, I will drop the pH to 7.0 and diligently brush for the rest of the summer I guess. Also, someone tell me if I should not use the abrasive side of a kitchen sponge to get this scaling off faster. This pool has had one problem after another, feeling pretty defeated right now.
A couple of noteworthy things to mention:
Providing some progress pictures of the pool over the past 5 days, a scaling spot I'm referring to, and current water chemistry in the attachments.
I am getting close to the end of slamming (and will start dealing with the scaling next). My CC is at 0.5 and I am no longer losing > 1.0 PPM of chlorine and the water is nearly clear. I am probably one or two good vacuums away from comfortably letting the FC drop to normal range. The problem I'm running into is that the algae has stained the scaling or maybe the scaling has trapped the algae below it (is that possible?). Am I good to stop slamming as long as there is no more loose algae in the pool or do I need to continue slamming until I can get the algae that has combined with the scaling?
And then as far as the scaling goes, I am unable to easily scrape any of it off because it is only on the floor of the pool. After I'm done slamming, I will drop the pH to 7.0 and diligently brush for the rest of the summer I guess. Also, someone tell me if I should not use the abrasive side of a kitchen sponge to get this scaling off faster. This pool has had one problem after another, feeling pretty defeated right now.
A couple of noteworthy things to mention:
- The TA in my area is SUPER high. It took me a whole season to get it to 100 in my previous pool.
- I will replace the liner next year if I can't get the scaling under control this season.
Providing some progress pictures of the pool over the past 5 days, a scaling spot I'm referring to, and current water chemistry in the attachments.
