Rough Plaster in Various Spots in Pool

[sulman531]

Hello all.

We have a 3 y/o gunite pool built by A/S in Southeast PA. Just this spring/early summer, we've noticed that several areas of the pool floor, steps and the swim out bench now have plaster surfaces that are rough, like sandpaper, and not at all smooth. I've tested the water semi-regularly, but will admit that I haven't done it as frequently as I should.

What is causing this plaster roughness and what can we do to remedy it?

Thanks,

Steve

 

[Texas Splash]

Hello Steve. It may be calcium build-up. Any chance you could post a full set of test results for us? Hopefully with a TF-100 or Taylor K-2006 test kit? Those are the only ones we recommend here. Those results may tell us the story.

 

[sulman531]

Water test results (our local pool service store did the analysis on a sophisticated device):

FC: 2.8 ppm
Salt: 3,200 ppm
pH: 7.7
Alkalinity: 145 ppm
Hardness: 200 ppm
CNA: 35 ppm
No copper, iron or other metals present
Water temp: 84 degrees

 

[Texas Splash]

our local pool service store did the analysis on a sophisticated device

- - - Updated - - -

Unfortunately, pool store testing has a bad reputation for inaccurate testing, testing under improper lighting, and inexperienced personnel. It only takes one of those factors to skew your results. You would be better served to test your own water with a recommended test kit like a TF-100 (link below) or Taylor K-2006. With results from either of those kits, we are better assured of YOUR accurate readings. We have more faith in your testing ability than a pool store. Your description still sounds a bit like scale/calcium build-up, although those pool store numbers don't really add-up.

 

[sulman531]

LOL. I have a test kit of my own, but it's not either one of the recommended kits. Will upgrade tonight.

If our problem is scale/calcium buildup, how would we fix it?

 

[Texas Splash]

Depends on the level of scale and age of the pool. Really bad pools might need an acid wash and scrub-down. Yours doesn't sound to be that bad. We have seen success with members who maintain their CSI level (on the Poolmath calculator) slightly negative to help encourage built-up scale to release from the pool surfaces. It's not a quick fix, but it has shown positive gains when used consistently and brushed frequently.

 

[pooldv]

You can also use wet/dry sandpaper to smooth it faster if it is really rough.

More here on scale, Pool School - Calcium Scaling

 

[sulman531]

Thanks Pat and Pooldv. Will get kit and retest tomorrow, and then take action based on results of Poolmath calculator. Have to go to Lowes anyway, so will also look for wet/dry sandpaper. Buildup isn't too bad, we've just noticed a few rough patches, so want to move to deal with it ASAP.

 

[jblizzle]

Realize that it is pretty rare to find the FAS-DPD chlorine test kit locally. Don't be fooled into thinking the DPD test is the same.