white chalk on pool walls

[tampa60]

Help, I have a 5000 gallon fiberglass pool and have a chronic problem with white chalky slime on the pool wall,
when the walls are brushed it clouds out the entire pool to white cloud, ohterwise water is fine but low ph problems, Iam about ready to surrender to a pool service....

[PoolDoc]

Unfortunately, chalking like that is usually related to UV (solar) mediated degradation of the resin based finish. Something similar happens with epoxy paint, and it's MUCH worse with poor paint, than with the best products.

Putting your pool under a screen enclosure would probably slow, but not stop, the problems. But, because I don't hear of this a lot, my guess is you got a pool from a lesser manufacturer . . . or a poor pool from a good manufacturer. (Maybe, a pool manufactured on Friday?).

Anyhow, there are a LOT of specialty pool contractors in Florida; maybe there's one that applies new gel-coat finishes? You'd be in a better position to check, than I am.

[glassguy]

Unfortunately a pool service company cannot help. This problem appears on all fiberglass pools in time. Initially, all swimming pool gel coat (the white or blue finish coat) is non-porous. This lack of porisity is what prevents staining at the water line and is why tile isn't needed on a fiberglass pool. The non-porous finish is why there is little to no algae, since algae must be able to cling to thrive, and why chemical requirements are greatly reduced compared to other pool construction.
With that understanding, you should appreciate the solution for you problem. When swimming pool gel coat degrades due to a combination of UV and chemically (or salt) treated water, it becomes porous and is completely worthless. This usually takes about 20 years and could be more or less, depending upon the manufacturer.
The only solution is to remove all the existing gel coat, and replace it with new gel coat. Then, no matter who manufactured the pool, it will be good for another fifteen to twenty years.

[PoolDoc]

Sounds reasonable to me.

[BigDave]

Good to know, as I consider our next pool.