If you own a fiberglass pool, you may have heard of osmosis — and no, it’s not just a science term from school. In the pool world, osmosis is a type of damage that can develop in fiberglass shells over time. Left untreated, it can affect the look, feel, and lifespan of your pool.

What Does Osmosis Look Like?

Osmosis in a fiberglass pool shows up as small blisters or bubbles under the gelcoat surface. Sometimes, when these blisters are cut open, they release a smelly, vinegar-like liquid. This is caused by water that has seeped through the pool surface and reacted with the resin beneath.

How Does Osmosis Happen?

Fiberglass pools have a waterproof gelcoat that acts as a barrier between the water and the fiberglass layers. Over time, tiny imperfections, cracks, or natural wear can allow water to slowly penetrate. This moisture reacts with the pool’s construction materials, creating pressure that causes those raised blisters.

Why It’s Important to Fix Osmosis Early?

While osmosis won’t cause your pool to collapse, it will get worse if ignored. The blisters can spread, the surface can weaken, and your pool’s appearance will suffer. Early treatment saves money and helps maintain your pool’s smooth finish.

At Bluvitalize, our resurfacing process includes:

• Draining the pool and fully inspecting the surface.
• Grinding back the damaged areas to remove moisture and contamination.
• Treating and sealing the surface to prevent future water intrusion.
• Applying a fresh fiberglass layer and new gelcoat in your chosen colour.
• How to Prevent Osmosis
• Keep your pool water chemistry balanced.
• Avoid leaving the pool empty for long periods.
• Schedule regular surface inspections to catch early signs.

Is your pool showing signs of osmosis?

Contact Bluvitalize today for a free inspection and resurfacing quote — we’ll have your pool looking smooth and sparkling again in no time.