Plaster Woes!

Our 12,000 gallon gunite pool is 10 years old. Used the 3 B’s first year, then added salt and a Watermaid SWCG. By the nature of these things always had higher pH and added a cup or so of Muriatic Acid every other day. Did enough Langlier calculations to know I was always between the 2’s. and annually draining 1/3 the water. Drained and DYI acid washed 5 years ago. I the past few years started getting what we thought were calcium growths “bleed” down the sides, maybe 6 places. Also noticed a discolored spot on the floor. Calcium hardness topped 400 at closing last fall so we decided to drain, acid wash and refill this month at opening. On a side note Watermaid cell gave up two years ago at age 7 and went back to bleach last year, just got a new cell in from Australia!

Drained pool to pasture Saturday and hit one “growth” with angle grinder and it was actually the plaster that was coming out, ended up chipping out a 12” diameter circle down to the shot-crete before reaching sound plaster! Other smaller growths could be smoothed out with flapper type wheel. Ended up with 8 or 10 spots that will have to be chipped out to take a 3/8” thick patch. I had bought a 3lb jar of E-Z Patch, which won’t be near enough!

The day got worse when I hit the blimish on the floor, not the bottom about 4’ deep. The 3” spot grew to a 18” diameter void clear to the concrete! Another small spot yielded an even bigger area. Through all the sliding around of tools and such I can hear another 4 to 6 spots that sound hollow and are no doubt delaminated as well! In all these areas the plaster chips easily, gets firm and unyielding when back into good plaster?

So what caused it? Using the E-Z Patch kits I’m looking at over 200 bucks so I called the builder, who actually used an out of town plastering company, to come look and give be a price to fix it. Debating DYI Acid wash, shouldn’t it be washed before repair if we don’t do a $$$ replaster? And if that’s the case do Pebble Tech, Quartz type plasters perform better in a SWP?

Also for safety I pulled the plug in one of the drain cans which was set in gravel, all my water disappeared so I put the plug back in. we are still in a drought…

Any constructive comments Welcome

Ken T. from North Texas!