White (calcium?) buildup on concrete

[Jetjohn6]

Still new to pool ownership. It's been going great following TFP since taking ownership. We seem to be slowly accumulating a white line at the water line on the faux stone portion of the pool perimeter. We're also seeing some to form at the grout between the tiles.

Is this calcium? Is there anything I can do with my chemistry to reduce or slow this accumulation? pH always tends to be on the high side that we guess to be 8-8.2. We add acid every week. I've attached a couple photos that didn't turn out the best but will hopefully help.
FC 4.5
pH ~7.8
TA 80
CH 310
CYA 40
Water temp 59°F

 

[mknauss]

Pretty standard in our area. You seem to have pretty low CH, mine starts at nearly that level. When did you last change your water?

Regardless you will get evaporite deposits as our high evaporation rates will deposit minerals at your water line.

Keeping your CSI slightly negative will reduce the accumulation. See Calcium Saturation Index (CSI) - Trouble Free Pool

 

[Jetjohn6]

Thanks for the reply. I haven't changed the water so it's at least 7 months old. Current numbers show our CSI at .17. Looks like keeping pH lower will help get that number negative. I'll work on that. It sure seems like we go through a lot of acid!

 

[jimmythegreek]

Sometimes its better to dose 2x a week and do less each time to keep it more consistent. Pool looks great. That faux rock is gonna be hard go keep looking good at the waterline going forward