Fiberglass Pool Resurfacing and Repair in New Braunfels, TX

Fading, chalking and scale

Some fading is expected. A fiberglass pool sits in the sun, and its color fades evenly and gradually, says River Pools, a fiberglass pool maker. Another maker warns that the wrong water chemistry can discolor, chalk, fade, etch or scale gelcoat, and may void the warranty. Its rule of thumb: scale forms whenever the pH is above 7.4 and calcium hardness is above 120 parts per million. It says there's rarely, if ever, a reason to add calcium to a fiberglass pool, and that concrete-pool standards don't carry over. Salt chlorine generators tend to push the pH up, so they need close watching.

Hard water is part of life here. New Braunfels Utilities says its groundwater sources carry extra calcium and magnesium, and that hardness shifts with location, source and season. Too little calcium has its own cost, though: in fiberglass and vinyl pools, soft water can attack metal fittings and heater parts, the plastering industry notes.

Hairline and spider cracks

Hairline cracks in gelcoat aren't unusual, says Latham, a pool maker, whose gelcoat is seven to eight times thicker than a normal coat of paint. Spider cracks form when pressure on the shell is more than the gelcoat can flex with. They're typically cosmetic, not structural, another maker says. Matching a repair is easier on a single-layer solid color than on a multi-layer metallic or flake finish.

Osmotic blisters

Blisters start inside the surface. Water passes through the gelcoat, meets contaminants behind it and forms larger molecules that can't get back out. That outward pressure raises a blister and can part the gelcoat from the layer beneath, the same maker explains. Gelcoat sprayed too thin can lead to blisters, and too thick, to cracks. Because blisters are a surface problem, that maker says a good warranty must name osmotic blisters, not just the structure.

The makers' rules come first, because draining can void a fiberglass pool's warranty. Here is what they say:

• The maker quoted above on blisters says that for most makers, an authorized dealer must drain the pool or the warranty may be void. Its method needs dry weather, groundwater pumped away and, typically, three braces 18 to 24 inches down the side walls.
• Another maker's manual says draining voids its warranty, and a shell drained without first relieving the groundwater pressure will buckle and crack.
• A third forbids draining, or even lowering the water below the skimmer, without its prior authorization. Draining can cause structural damage, blisters or gelcoat cracks, it says.
• A fourth maker's lifetime warranty covers the gelcoat against osmotic blisters for 10 years, and draining the pool voids it.

Day to day, the first maker on that list recommends keeping the water a third to halfway up the skimmer and never draining a fiberglass pool. So check your own pool's warranty, and who its maker allows to drain it, before any water comes out.

Groundwater, clay and the drought plan

Clay holds water around a pool longest and sandy soil the least, the same maker notes, and that water pushes up on an empty shell. East of the Balcones Escarpment, which crosses eastern Comal County, the Blackland Prairie soils are mainly deep clays. For Houston Black and similar clays, the federal soil survey lists very slow permeability among the limits. Vinyl liners can bubble and float under the same uplift, which our pool liner replacement page explains.

The city's drought plan adds its own limits. Since October 1, 2026, it has allowed a pool to be drained only onto ground that absorbs the water. The drain must also be to lower rainwater, fix a part that has become hazardous, or repair a leak. Ask New Braunfels Utilities whether your job qualifies before setting a date.