what causes bubble in the pool

[hspr4]

I had my pool resurface three years ago with fiberglass. Now bubble are starting to appear. what causes these bubbles and how do you fix it.

[geeman]

the fiberglass is seperating from the original material underneath (probably plaster). I've seen this happen to almost every fiberglassed pool I've seen. You could drain the pool and cut out the bad area to have it patched. Hopefully the glass company is still in business.