The look and feel of a pool environment can be greatly enhanced with colored pool plaster. That cool blue look gives a magazine presence to a back yard and it’s a popular feature that a lot of pool owners are willing to pay the added expense of. The downside is, that with regular chemical use and just time itself, streaks, blotches and pigmentation discoloration is likely to happen, and it changes the feel pool owners paid for.

There are a number of reasons, and many are often preventible, that colors can fade or turn white. Scale can be deposited onto pigmented plaster surfaces by out-of-balance pool water. Keeping a pool’s water balanced is important for a lot of reasons, discoloration is one.

Another reason for color changes is simply due to workmanship and material selection. Quartz and pebble finishes have other elements in them that might not make the grade, and their wear and discoloring might be questioned as calcium scaling due to out of balance water, but the reality is, the quality fo the applied surface just might not have been that great to start with.

The whitening of colored plaster may be caused by soluble calcium ions in the plaster dissolving into the pool water due to a lesser quality plaster workmanship and has nothing to do with water balance at all. When calcium dissolution occurs, it means the plaster surface is deteriorating, losing density, and becoming porous, even though it usually remains smooth. When this porosity develops, a whitening of colored plaster is the result. Making acid washing a remedy might not remove the discoloration and is likely to cause further damage to the surfaces if this is the case.

Why does colored pool plaster turn white

Calcium Scaling versus Porosity Issues

Calcium scaling is caused by out-of-balance water and usually deposits a layer of calcium carbonate throughout a pool causing the surface and fixtures to whiten. It even feels rough to the touch. Light scraping or sanding with sandpaper will take this away.

If the whitish discoloration appears as streaks or blotches and is smooth to the touch, the problem is probably not calcium carbonate scaling, but rather a porous surface that is deteriorating faster than normal.

Calcium hydroxide and calcium chloride are two factors reduced by the plaster in a pool when it’s cured. These two things can lead to a porous, yet smooth surface. Calcium carbonate, a primary plaster constituent, is insoluble. It’s easy to assume that calcium hydroxide and calcium chloride can only be dissolved by aggressive pool water, when in fact, both elements can actually be dissolved, even by balanced water. That means’s likely something other than aggressive water is the culprit for porosity developing and the whitening effect. When those calcium ions slowly dissolve away, that process can remove color pigment and is another reason for a whitening to develop.

Other Reasons For Discoloration

Another reason for color loss is that some plasters use organic pigments in their mix. Organic pigments can be bleached by the presence of chlorine or other oxidizers, and even by direct sunlight.Organic pigments are less expensive than inorganic pigments, but they generally cannot withstand a swimming pool environment for long. This bleaching action occurs even if the plaster workmanship is of high quality. Some plaster mixes contain two pigment colors. If one is organic and becomes bleached, that color will simply disappear leaving the other non-bleachable pigment visible as the sole color.

A Remedy Porous Plaster

A very extreme acid treatment is often implored to restore the original color of the plaster. However, these acid treatments etch the plaster and make the surface rough. This also causes increased porosity and surface deterioration. It reduces the life span of the pool surfaces and the pigment color is likely to fade away and turn whitish again.

A better alternative for removing a porous and whitened plaster surface would be to sand and polish the plaster. This removes the porous material and restores a hard, dense, and smooth surface to the pool. Unfortunately, for pebble finishes, sanding and polishing is virtually impossible, leaving the more harsh alternative as likely, the only option.