Osmosis in Fibreglass Pool: A Sign that your Pool Needs Renovation


REEF POOLS - Osmosis repair, fibreglass pool resurfacing

Osmosis is one of the worst issues that can happen with fibreglass pools. Popularly known as Black Plague, Osmosis is deterioration of top gel coat of fibreglass when air or contaminated water seeps through the pool’s lining, causing the pool surface to develop blisters which later cause algae growth inside the pool if cracked.

Reasons Why Your Fibreglass Pool Has Osmosis

There are a number of ways that can cause osmosis in your swimming pool, but are generally most of the black plague issues are related to age, pool’s quality, how it was installed, and how you maintain it.

#1. The Type of Materials Used

The quality of material used for manufacturing your fibreglass pool gel coat, coated laminate, and resin can affect the blister resistance of your pool.

#2. Faulty Techniques of Manufacturing and Construction

Most of the osmosis issues are due to the type and construction of laminate which is placed on the pool’s interior surface. Improper construction involves fibreglass pools coated with a cloth mat soaked in resin which may expose the pool to water saturation resulting in brownish black blisters.

#3. Maintenance

Maintenance or more likely lack of it can accelerate osmosis formation.

  • Raised exterior and water temperature (above 30°C) may make your pool’s coating porous and can make it more reactive towards chemicals which may elevate the rate of osmosis.

  • Secondly, excessive use of chlorine-based chemicals in water treatment weakens the coating surface, making it more prone to the formation of the black plague.

What are the Stages of Osmosis and How to Identify it