Help! Fibreglass pool is blistering.

[Peekaboo]

We moved to France in August and inherited a Fibreglass salt water pool.  Having just emptied it in readyness for the winter we have noticed several blisters appearing.  We are not sure how old the pool is (at a guess over10 years old), the colour looks faded and the surface is quite marked. Can someone advise on whether the blistering is a problem and what can be done.  Also, if there is a paint that can be used to rejuvenate the colour.

Many thanks

Peekaboo

[Chezstevens]

If your pool is suffering from osmosis - same problem for fibreglass boats in the sea - then you may find the best solution is to put a liner in.

regards

Vern

[Peekaboo]

Thank you for your swift response.  I think we might have a problem with putting in a liner.  We have an integral jacuzzi effect set into the main steps of the pool, lights and a water jet mechanism at the far end of the pool (I think you are meant to be able to swim against it, so far only a gentle doggy paddle keeps you from banging your head at the other end of the pool).

[Will]

It certainly sounds like the same problem that affects boats, commonly known as osmosis, or osmotic blistering, though that's a bit of a misnomer. Even in boats it is mainly cosmetic, though of course if allowed to deteriorate too far (which will take many years) the structure of the laminate can break down.

I doubt if fitting a liner will solve anything, though it would hide the problem. However in your case a liner is not practical. Osmosis can be repaired, and many boatyards are very skilled at the work. It is a very long drawn-out process, though. There are several methods, of varying effectiveness. One of the most thorough involves removal of the gel coat (the shiny, hard top coat) at and around the affected areas, completely cleaning and decontaminating, then drying out over a long period, usually using heat and dehumidifiers. This is followed by re-coating with a special epoxy coating to replace the gel coat. As the work really needs to be done in a temperature- and humidity-controlled workshop, you may decide to live with the blisters. After all, a pool with advanced osmosis is not in danger of sinking - just leaking slightly.

This web site explains it quite well, though there are other methods of dealing with it, which you will find using a Google search. http://www.yachtsurveys.co.uk/faq_osmosis.htm

[Poolguy]

You might also examine your sanitization regime

very carefully, as quite often chemical imbalance is the culprit for the attack

on the fibreglass and gel coat.

Quite often a salt system will produce very 'aggressive' water, when the pH is

well out of balance as many salt systems in France are installed without pH

controller. This is in addition to the attack from the salt itself. Also if

your Total alkalinity is out, you'll find it difficult keep these elements

stable - normally it should be between 80-120ppm

You now have a wonderful habitat for bugs to grow in places where it is

blistered which are hard to clean, all of which does not auger well for a hygienic

pool water. Not good for bather health and extra work for you each week.

I suggest that you take urgent steps to repair the surface of your resin shell

and examine your regime of sanitization with a view to changing up to a more

modern and effective technology to chlorinate and balance pH.

As for the repairs in the post above Will suggest the professional approach

which will I am sure produce a handsome and successful result. However, it is

possible to DIY it using an epoxy paint to replace the gel coat that you remove

around the blistering. It will not look as handsome but it will seal the

fibreglass and stave off the hygiene problem for a while.

In the last analysis though, you should accept that your resin shell is on a

down hill bender, and there is a limit to the time that you might consider it to

be giving acceptable service. For if it has happens in one or two places then

it is sure that other places are in the process of pusstulation (?). Eventually

the whole surface will I suspect become unserviceable. Such is one of the many

drawbacks of Resin shells.

As an anecdote, liner manufacturers boast that they can make a liner to suit

ANY shape, for my part I have not had the opportunity to prove that their claim

is idle.

If you need specific help then PM me and I'll help if I can.

Andrew