We (my wife and I) definitely have a problem. I'm just not sure whether it's algae or not. A few months ago, we bought a house with a pool that had been neglected for a few weeks. It was green and cloudy, but not near as bad as one neglected for months or years. THAT was definitely algae. We bought a TF-100 kit, and learned the ways of SLAM'ing. In about a week, we got it nice and blue, and sparkling clear. But over the last month or so, we've had a couple of outbreaks of green. Slight green. A haze, or maybe just a tinge of green, along with cloudiness. Algae, I assumed. The first time I didn't do a full SLAM. I just elevated the FC a bit (10 or so as I recall), and it got blue and clear again. This weekend, it went green and cloudy on us again. A couple of nights ago (after sunset) I started a SLAM. I started off by dropping the pH to 7.2, then hitting it with bleach to get an FC of 14 (as recommended by Pool Math). I must have overshot a little. When I checked FC a couple of hours later, it was 18. I guess I'm off a bit on my water volume. This morning before sunrise, I checked it again, and it was 18.5, It went UP 0.5 ppm. I'm guessing that there's a little variability in the testing. Maybe one test had a slightly different amount of water, or something. Anyway, would this suggest that we're battling something other than algae?
It also seems that there routinely greenish stuff on the bottom. When I brush it, I see greenish clouds form behind the brush. The more I brush it, the more the pool clouds up and turns green and hazy. But this green doesn't seem to consume FC. We're testing on a 2 hr interval right now, and we didn't see FC drop until after sunrise.
This morning, it looks a little better. Bluer, but still cloudy. Here's a log of my current SLAM activity:
Added ~1 qt muriatic acid
Added 3 gallons of bleach.
Added 1/2 gallon bleach
FC isn't dropping as I'd expect with an algae bloom. What's going on?