One tiny spot that will not go away

[Jen77]

Hello,
I posted once before and got some really good help here. Hoping someone can help me again as I am at a loss. My pool water is clear. Here are my levels at the moment:
FC 11.8 (Coming down from a slam)
Alk 80
PH 7.4
CH 240
CYA 40
We have one small spot on our liner that some type of algae keeps growing back (see photo). I slammed the pool and got up to 30. I did the OCLT and this morning my level held at 16 and this morning it had not come back. After work, I came home to find that the spot had come back slightly and my chloring level is down to 11.8. Just at a loss as to why this keeps coming back in this one small spot. Any help would be greatly appreciated.

 

[Jen77]

Hello,
I posted once before and got some really good help here. Hoping someone can help me again as I am at a loss. My pool water is clear. Here are my levels at the moment:
FC 11.8 (Coming down from a slam)
Alk 80
PH 7.4
CH 240
CYA 40
We have one small spot on our liner that some type of algae keeps growing back (see photo). I slammed the pool and got up to 30. I did the OCLT and this morning my level held at 16 and this morning it had not come back. After work, I came home to find that the spot had come back slightly and my chloring level is down to 11.8. Just at a loss as to why this keeps coming back in this one small spot. Any help would be greatly appreciated.

I should add that it does go away once brushed, but usually comes back a couple hours later. Overnight last night was the longest it was gone, but was there slightly when I got home from work.

 

[ajw22]

Run your pool at half SLAM FC for a while and brush it often.

 

[Jen77]

Run your pool at half SLAM FC for a while and brush it often.

Okay, thank you so much for replying! I will try that.