Will A Fibreglass Pool Stain?

No one likes dirty water but add staining and blemishes which mar the appearance of a pool wall and no will want to jump in! The good news is that fibreglass pools are built in a way so they don’t easily stain. To prevent lots of staining remove any foreign objects as soon as you see them and keep a check on balancing your pool chemistry throughout the year. Remember that ‘prevention is better than cure’.


Fibreglass pools – extra protection from staining

Fibreglass pools have a special gel protective coating which prevents bad stains. If your fibreglass pool does have a stain, it’s usually from one of the sources:

  • Organic matter
  • Build-up of metals
  • Oxidation of the fibreglass shell
  • Scale deposits

An effective way to determine whether the stain is organic or metal in nature is to rub a Vitamin C tablet on the stain. If it goes away, it’s metal. Vitamin C contains ascorbic acid known for its ability to remove metals stains.
Under no circumstances should you ever drain your pool to clean any markings. This is a definite no go, as it will cause the pool’s shell to crack with potential damage occurring with the surrounding hard landscaping.

Brown stains

Brown stains are usually a metal build-up which occurs from the chemicals you use to balance your water. Iron is one of the main culprits causing ugly rust stains. Rusted metal accessories and equipment can also cause stains. If copper is the culprit, the stain will be more turquoise in colour.


White stains

Hard whitened patches on your pool are likely to be calcium scale deposits and will have built up over a long period of time. They usually form along the waterline of your swimming pool and are a strong sign that your pool does not have total alkalinity or has the right PH balance.

Any good calcium remover product will eradicate the problem. Never use a pumice stone and elbow grease as you’ll scratch the fibreglass pool.

Yellow stains

Excessive salt added to a saltwater pool can also cause staining creating a yellow colour. Too much liquid chlorine and iron deposits may create a stain of a similar colour.

Black stains

Black marks are usually the result of being too generous with algaecides. Algaecides contain metals – copper, silver and nickel – all of which leave unpleasant dark marks. They may also be cobalt oxide stains. The cobalt comes from osmosis of the gel coat, the giveaway sign is when there are blisters at the side of the black spot.

Green stains

Green stains are usually organic stains from algae growth, leaf, falling twigs or green debris which has been washed into the pool and settled for more than a week. Stormy, wintery weather will inevitably accentuate the problem.

Stains in your pool can be ugly and difficult to deal with, so keep on top of your pool chemistry to prevent them. If you have any questions about fibreglass pools or their maintenance, we can help. Factory Pools Perth manufactures, fits and installs fibreglass pools and spas. Each comes with a lifetime structural warranty. Give us a call to find out why we’re one of the top pool companies in Perth.

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