I recently acquired a beachfront property in tropical Thailand with a swimming pool made of plaster. The pool is only 1 year old, and yet I already see some pop offs on the plaster surface. Furthermore, the pool has been filled using ocean water!

When I spoke to the former owners, they told me that during the time they were building the pool, they couldn't secure fresh water to fill up the pool (as the property is in a remote island). So they decided to pump ocean water into the pool. And they have not replaced the water with fresh water since then. The water though is quite clear -- they have managed to filter it really well. But tastes a bit salty of course!

So my question is, could using the ocean water in a swimming pool that is built to hold only fresh water adversely affect the pool plaster and cause the pop offs?

Welcome, and I am going to say, yes, that your on the right track with your thinking.

http://www.troublefreepool.com/pool-school/pool_plaster_start-up is one of the articles in pool school, and it specifically says no salt for the first 30 days, let alone ocean concentrations of salt. There are other articles on plaster as well that may shed some light on this. Specifically making sure the calcium levels are correct. There may be other things, as I am certainly no expert on this.

honestly, I am not sure what is meant by pop-off, but I imagine the best thing to do at this point is to get the water chemistry in check, and then repair any visible damage as needed. Hopefully that will not be very hard, as it sound like you have a very nice set up there. Pictures are welcome.

Boy, if I had a dime every time I heard that I'd have........well, 1 dime.

Welcome to the forum

Google (bottom left on page) has some interesting info:

post32010.html#p32010

seawater-pools-t9088.html

Can you post a pic or ten for us?

Thanks for the quick response! I really appreciate the input.

The pop-offs I was describing are patches of plaster that cracked and popped off from the surface, so you have some sort of crater where the pop off occurred. Not sure but reading from some articles on plaster problems, I think what happened is something close to what is called delamination. Is this the

Oops! Sent my message prematurely.

Anyway, I just wanted to ask if how I described the pop-off makes any sense, and would the ocean water have caused the plaster to breakdown as such?

I will post the water chemistry and photo soon!