I've had black specs in my pebble that have been increasing over the past few weeks/months. I have a 3 year history of not maintaining my water chemistry very well up until a couple months ago when I found this site. With the exception of CH (which I plan on doing a drain in the next week), I've kept a good eye on my numbers lately. In the past week, my chlorine got knocked down to zero because my SWG breaker got tripped and I didn't test for a few days. I'm currently shocking it. Earlier this week, I went into the pool and took a pool wire brush to some of the black spots (which have a smooth, slimy feel to them) and they will scape off and disintegrate with some hard rubbing. Do you guys feel that black algae is the culprit here?
My current reading:
TC: 15.5 (more chlorine was added after reading to obtain shock level per pool calculator)
pH: 7.8 (MA added to obtain 7.4 per pool calculator)