My Story.

[AnnaK]

Once the FC goes down to below 5 I might shock it again, just to get rid of the algae.

In your original post you said you had an algae spot to the left of the steps. That's the shady area in the photo, correct? It's not unusual to get some minor algae growth in shaded parts, especially when combined with lower circulation there.

Rather than shocking the pool again you could just pay particular attention to that area when you're brushing.

 

[astroprojector]

Thanks everyone for the help.

I think I got it under control now. I aerated the pool to bring the TA down and right now it is at 140 with pH at 7.5. The FC stays at 7 for several days now. I guess everything has normalized except the CYA. I still not sure what I have there and also the results for calcium test I performed was outrageously high, over 400. Eventually I will drain the water half or completely when I decide to re-plaster and re-tile the pool, but have to do it in the fall or winter when the water shortage limits are removed in California.