Frequently Asked Questions

What is Osmosis?

Osmosis, also known as black plague, refers to bumps or blisters that appear on a pool’s surface based on a failed watertight seal.

These imperfections exist permanently, or may come and go over time. The bumps that arise are often one to four inches in diameter, feel hard or porous to the touch, and may not pop or crack when stepped on or pressed. Some may leak a brown or black tar-like substance, causing alarm in pool owners concerned with possible safety consequences. Treatments like staining or popping will not diminish the effects, and shocking with high doses of chlorine can only exacerbate the problem.

Why does Osmosis Occur?

Osmosis occurs when air and water escape through a pool’s lining.  Generally these issues can arise in any number of ways, but are generally related to the installation and care of a pool.

What do Osmotic Blisters Look Like?

They are normally the size of a 20 cent piece or smaller and look just like you would expect a blister to look…like slight bubbles that are raised on the surface of the pool, they can also appear like black spots.  They do not go away and unfortunately there’s no quick fix either. 



How can Osmosis be Repaired?

As stated above there is no quick fix, unfortunately the existing interior needs to be grinded back to expose all of the Osmosis.  The Osmosis is then removed and a filling agent is applied that is suitable for fibreglass pools.  New fibreglass matting is then installed and fill coat and final top coat are applied.

Why is fibreglass pool resurfacing better than plaster, pebblecrete, vinyl pool liners and epoxy pool paint for the resurfacing of your swimming pool?

Several reasons to consider fibreglass resurfacing as an alternative to plaster, pebblecrete, vinyl pool liners, epoxy pool paint for swimming pools and other products:

  • Fibreglass is stronger than plaster, pebblecrete and vinyl liners.


  • Fibreglass has its own structural integrity regardless of what it is applied to.

  • Common failures with plaster, pebblecrete pools are: cracking, chipping and “pop-offs” because it does not bond well.

  • Epoxy pool paint has a shorter life span without the structural strength that fibreglass offers

  • Bonds well and is not susceptible to these failures.


  • Withstands earth movement and shifts in a swimming pool, while plaster and pebblecrete will crack and chip almost immediately.  

  • Provides superior resistance to stains, algae, and discoloration.   

  • Life expectancy is rated the highest out of all resurfacing products available.

  • Is a superior pool resurfacing product. 

What is the warranty period?

SEQ Fibreglass stands by our 5 year warranty on our fibreglass surfaces.

​How long will my pool be out of action whilst it is being resurfaced?

Depending upon the size of your pool and the amount of Osmosis our process takes anywhere from 3 to 5 days.  There is then a curing period of 7 days prior to your pool being able to be filled with water again.