Calcium deposits?

[mike.stocker]

Howdy all, I’m in the middle of a SLAM (day 6) and my pool is looking pretty good but I still haven’t passed all three tests. That said, I opted to get in it today (hopefully that’s okay) and I am noticing what feels like sediment caked on the walls that is extremely difficult to scrub off. Could that be calcium deposits? I tested everything yesterday and my CH was 225. Is that test accurate during a SLAM? I know the FC was low for a SLAM, I added more chlorine right after the test to bring it back up. Any ideas? Let me know what other information I can provide. Thank you!

PoolMath Logs

 

[mknauss]

Could be calcium. The CH test is accurate during SLAM.
Was it there earlier in the year?

 

[mike.stocker]

I’m not sure, unfortunately. I bought the property a few months ago and only in the last week have been able to start cleaning and opening the pool. So this is the first time I’ve ever been in it.

 

[mknauss]

Likely from last winter.
Once your SLAM is complete, keep CSI below -0.3 and brush to remove the scale.