Reading through numerous posts, wondering if someone might be able to help me out. I had my pool replastered 5 months ago. Within a month I noticed grey mottling on the sides and on the floor of the pool. I was trying to figure out if it was scaling or not, but I have come to the conclusion that it was a result hard troweling. It was in the upper 90s (North Texas) when the plaster was applied and the guys were trying to get the pool done before it rained.

I purchased a calcium eraser from the store, when I used it on the spots on the wall, it created a cloud of white dust. Thoughts? Is this a result of hard troweling? What can I do other than sanding down all of it? I have read that acid washes don't seem to help with this issue.

Thanks,

Kyle

The first thing to do is post a full set of test results and how you got them.

It sounds like scaling but without test results and a little more info it's a shot in the dark.

FC=7
CC=0
CYA=70
PH=7.4*
TA=90
CH=450

*I have a fountain that runs consistently and my PH fluctuates quite a bit from 8.0 to 7.2 after I add MA.

CH has had been at 350, but then I did a super shock to kill some mustard algae. In June I was a pool noob, but quickly found this site. For about 3 weeks my PH was above 8.0 and my TA was around 130.

Given your numbers and the fact that you have high pH, I'd say chances are that it's scaling. Keeping your pH as close to 7.2 as you can will most likely dissolve it over time.

You should post some pictures of the discoloration. Are the grey areas rough to the touch? If smooth, then perhaps it is not calcium scale. Does sanding the grey mottling spots remove the discoloration? If it is calcium scale, then I would think that the grey color would be removed fairly easily since this is a new plaster job. And sanding a plaster surface would probably cause a white residue to come off regardless. Does a white cloud come off on non-discolorerd areas?