temporary drain and fill "discolored" my plaster

May 24, 2010
200
Dallas, TX
Specifically, my pool was resurfaced with pebble sheen (Riverbend Sandler's version of it here in Dallas) a little over a year ago. I don't remember the color name but it was a blue-colored plaster between the pebbles for an overall bluish look. I did a partial drain and fill (got it about half way down)- at most there was exposed surface for no more than 36 hours (and during daylight, it was mostly cloudy, so I wasn't getting intense sun). I noticed that the surface looked a little more "gray" when exposed; I continued to notice it after the refill, though I didn't pay attention as I was in the middle of fighting some awfully cloudy/dirty water (soil runoff due to horrendous rains). This was a few weeks ago. I'm now noticing that gray tint continue to stay around, and it ends right where the waterline got down to.

PB told us the surface would get bluer over time. So possibly lack of water and direct sun exposure set me back a bit. It took a few days to get chemistry back after the fill but it was never far off (pH no less than 7.2, CH no less than 50-100 for a week, and Alk no less than 40-50 for less than 2 days).

Not sure what else would be going on here besides a little temporary drying out? Scrubbing did nothing for it so there's no layer of something or other that's discoloring it.
 
It could have been from the sun when you drained it. I don't know if time will correct it or not> Hopefully someone can answer this for you and set your mind at ease.
 
Draining a plaster pool is always fraught with difficulties. Here in AZ where it gets blazing hot in the summer months (heck, May-Sept is blazing hot!), draining a pool under any circumstance is not at all advised. The plaster surface will dry out very quickly and the differential temperature between the plaster surface and the gunite below can get to the point where cracking can occur. Draining a pool half way is a bit worse because then you would have half the plaster surface at air temperature and half the surface of the pool at water temperature which can easily be a 20-30F difference (here in AZ).

I suspect what happened to your pool surface is that, as the water line drained down, the exposed surface had water on it that dried out and left behind whatever solids were in your pool water (salts, calcium, stabilizer, etc). That probably formed a thin layer of grayish colored evaporite kind of like a gigantic water stain. Then, when you filled it back up, it took time for the new pool water to dissolve those mineral stains away. Calcium carbonate is particularly slow to dissolve once it forms a scale. With consistent management of your water balance and maybe aiming for a slightly negative CSI, any remaining stains should lighten up over time.

Glad it worked out for you.
 
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