Hi,
I have a 10 year old inground pool that is enclosed with a sunroom. A few years ago I noticed some small areas on the coping were blistering. The condition has continued and I'm now trying to figure out what to do about it. I have attached a photo showing what some of these distressed areas look like. I could use some thoughts as to what can about it.

Some general info:
Location is Chicago area
Water chemistry is good. We did however have an issue a few years ago with pool center that messed up up water balance and had to drain the pool.
Size is 16x32.

Thanks for any help or insight on this issue.
Mike

Hi mikeT and welcome to TFP

Because your inground pool is enclosed in a sunroom, it could and/or would be considered an indoor pool which puts a different twist on things.

Please post a full set of water test numbers and give all the info included in this article.

Also, if you have some pics of the overall set-up, including the sunroom, it could prove very helpful.

Folks will be around soon to give you some ideas

That looks like acid ate it. I suppose you could fill it with an epoxy filler, sand it smooth and spray paint it with Rustolium.

Scott