Epoxy Pool Coating - Chalking Prevention

[Chinalc]

Epoxy pool coatings are known to “chalk”.

I am think of repainting my pool with epoxy but want to prevent it from chalking. I have seen postings online saying to keep the alkalinity levels at 150ppm and to ensure the calcium level is at least 300 ppm. I have tried this but the epoxy still chalks after 1 season.

I am thinking to add a clear epoxy on top of a fresh white epoxy coating.

Has anyone tried this and does anyone have any comments as to whether this would prevent chalking? My logic is that with a clear epoxy, if it chalks, it’s clear and won’t cloud the water.

Would love to hear your comments.


Thanks,

Andrew

 

[ajw22]

Welcome to TFP.

My understanding is that with modern environmental regulations there is no good pool paint that does not chalk eventually.

I have my doubts that a clear layer of epoxy will bond and adhere well over the paint layer.

 

[Kale46]

I bought some paint from Japan (two pack which cost twice as much as epoxy). Have had it for about 3 years without chalking and colour is still good.

 

[JoyfulNoise]

In the US (and I bet Canada too), pool paint is not very good quality. The best you’ll get is a season or two before it begins to disintegrate. Many of the “old” pool paint where made with some pretty nasty chemicals that made them very durable but are highly toxic to the environment.

“Chalking” of polymer surfaces is mainly an issue of polymer hydrolysis (water attacking and breaking down the chemical bonds) and/or unreacted monomers that are left behind and are reactive to water and oxidizers. It has nothing to do with calcium carbonate saturation. pH, UV, oxidizer levels, etc, all play a role in the rate of hydrolysis. There is no stopping it and very few ways to slow it down. Once the polymer bonds start to cleave, the surface becomes microscopically porous and mechanical weaker than the bulk. This is what leads to a chalky/hazy appearance and the eventual sloughing off of surface layers.

Put a human body in water long enough and the same thing happens to skin....hydrolysis and sloughing off of tissue layers....don’t ask how I know that ?