Calcium on your Fiberglass pool?

In most cases, our calcium remover kit completely clears the white calcium buildup on fiberglass pool surfaces. It also restores the smooth blue finish and has prevention products to help keep it looking good. However, if left untreated, this white build-up will spread across the pool surface and become thicker and more noticeable over time.  For this reason, we strongly suggest doing something about it as soon as possible.  Our fiberglass pool stain remover compound removes calcium from fiberglass pools without draining.  It works by softening and dissolving the white calcium build-up without acid washing.

Calcium on Fibreglass The Pool Stain Removers 1

These pictures show heavy calcium scale formation in need of our fiberglass calcium remover.

Calcium on Fibreglass The Pool Stain Removers 2

Our fiberglass pool stain remover treatment without draining or acid washing.  Our customer was thrilled with the result.

calcium on fiberglass

A thin layer of calcium scale has formed on the waterline of this renovated fiberglass pool.

calcium of fiberglass pool

Our fiberglass pool calcium remover fixed this issue without draining or acid washing.  Our customer was thrilled with the result.

Causes of calcium buildup on fiberglass pools

Whitening or discoloration on fiberglass pool surfaces is normally a result of one of the following factors. We have ranked them in order from most common (1) to least common (5):

  1. Calcium buildup on the fiberglass surface.
  2. Pool interior is in the final stages of ageing (25+ years).
  3. Bleaching of color from gelcoat interior.
  4. Undissolved sodium bicarbonate has bonded to the pool surface.
  5. The gelcoat layer has not been cured properly in the factory.

1. Calcium build-up on the pool surface

High pH levels in the pool water may cause calcium on fiberglass pools to precipitate onto the pool surfaces. When this happens, it often leaves a thin white gritty layer.  As the picture shows, this white layer becomes very noticeable if the pool water drops below its normal level.

To help prevent calcium, we suggest regularly testing the pH and calcium hardness levels in your pool water.  Remember, High calcium (above 4000ppm) often occurs for two reasons.  First, too much calcium chloride (calcium increaser) has been added to the pool water. When this happens, it leads to calcium formation. Secondly, calcium-based granular chlorine will increase the calcium hardness levels in your pool. If your calcium levels are rising for no reason, then it is likely that granular chlorine (calcium hypochlorite) is the cause.

Ask your pool manufacturer before adding calcium

Before adding any calcium chloride to your pool water, contact your pool manufacturer (not your pool store) and get the suggested calcium levels for your pool. Remember, each fiberglass pool manufacturer recommends different calcium levels.  Finally, check that your pool store water test computer knows that your pool surface is fiberglass and not plaster.  This is because plaster pools use different water chemistry settings.

As the pictures show, our treatments remove calcium from fiberglass pools without draining the pool water or acid washing.

2. The pool interior is ageing

Fiberglass pools typically pass through two phases as the surface begins to age.  Firstly, the gelcoat blue color will slowly fade to white over time.  This fading happens because of chlorine in the water, years of sunlight and unbalanced water which all take their toll on the surface color. Remember, this color fading, which often starts after 15-20 years, is normal. This is not an indication of a faulty pool interior. Remember, if your pool is slowly losing color after 20 or more years then ageing is the likely cause.

The second stage of ageing is when fiberglass pools (20-30 years old) start to develop a persistent white powder that appears when the pool is brushed.  The powder is actually degrading gelcoat which has broken down over time.  This white powder will eventually disappear in sections of the pool revealing the lower layers of fiberglass which are often dark brown. This breakdown is common in high friction areas such as steps, benches and ledges. Remember, the best way to extend the life of your fiberglass pool is to maintain the water correctly.

Salt Water pools in Winter

Remember that saltwater chlorine generators continue to add free chlorine to the pool when they are running.  So, if a pool cover is protecting the free chlorine from sunlight then the chlorine levels will continue to rise when the pool is covered.  This means that the free chlorine levels can rise to dangerous levels quite quickly.  We have seen many cases where the free chlorine has exceeded 40ppm in these situations. So if you are covering your pool, ensure that the chlorine production is reduced dramatically as very little chlorine will be required.

Calcium on Fibreglass The Pool Stain Removers 5
This partially drained fiberglass pool shows the white calcium formation. Notice how thick and widespread it has become along the walls. This client did not attempt any type of treatment hoping that it would just disappear over time.
calcium on fiberglass
This Fiberglass pool has a heavy layer of calcium formation on the surface. You can clearly see that the areas where the calcium has flaked away that the gelcoat color is in tact and not bleached.

3. Bleaching of fiberglass or gelcoat

Bleaching in a fiberglass pool happens when the pH and the chlorine levels are both very high at the same time. Remember, if the pool water remains unbalanced, with very high chlorine, it may start bleaching the surface.  Although fiberglass pools are required to resist bleaching due to mild water imbalance, they cannot withstand unbalanced water for very long so fading can occur. When winterizing your pool, make sure that your pool guy does not over chlorinate the pool.  If they do then it could discolor over the winter due to the high chlorine levels in the water.

Gelcoat bleaching from unbalanced water is often smooth and is non-responsive to cleaners and acids. In some cases, rubbing the surface with fine sandpaper can appear to remove this discoloration.  However, doing this incorrectly will only remove the bleached gelcoat layer in your pool. Remember, rough sanding the gelcoat will leave your pool susceptible to future staining and reduce the life of your pool.  Only rub the pool surface with approved products.

Careful with pool covers

Some pool owners feel that testing the water during winter (or when a pool cover is on) is not needed. Often, these same pool owners are horrified when they remove their pool cover and discover extensive surface bleaching. Remember, it is a good idea to check your water during winter, even if the pool is covered.

Our treatments can sometimes help with surface bleaching.  However, there are cases where nothing can remove the visual effects of pool surface bleaching.  This is because the pigment within the gelcoat resin has been oxidized by chlorine.  Please contact us for further information if you feel your pool may have this issue.

Gelcoat bleaching Fibreglass
Possible Gelcoat reaction with the pool water. Notice the smoothness of the white film and the distinct separation between the vivid blue and white along the waterline. Our treatments are sometimes effective with this issue.

The layers of a fiberglass pool

The diagram below shows how the layers of material are bonded together.  Notice that most of the thickness of a fiberglass pool comes from the structure and not the blue decorative layer on the surface.

layers of gelcoat
This sectional diagram shows the layers of a fibreglass pool from top to bottom. Notice that the pool water can slowly circulate through the top surface layer of gelcoat. This process can allow the gelcoat to be effected by poor water chemistry.
gelcoat fading in fibreglass
In this image the light blur gelcoat is breaking down revealing the brown fiberglass structure under it. This pool is 32 years old.

4. Adding undissolved sodium bicarbonate to the pool

If an undissolved alkalinity increaser (sodium bicarbonate) is sprinkled directly into the pool, it can form a stubborn white film to appear on the pool surface. To avoid this, ensure that the buffer is dissolved in a bucket of water before it is added to the pool.  Remember, when alkalinity increaser is first added to water, it will start as milky white and then as it dissolves, the water will become completely clear. Remember, once the water is clear in the bucket THEN add it to the pool.  Likewise, it is always best practice to balance the pH before adding sodium bicarbonate.

5. Gelcoat not cured correctly during manufacture

In very rare cases, the gel coat can discolor and remain white if it has not been cured properly during manufacturing.  If your pool has this issue, it will become obvious within the first few hours after the pool is filled with water. This discoloration occurs because the uncured resin on the surface is very porous.  This allows the water to penetrate into the surface resin and bleach the pool surface.  Remember, this bleaching is permanent and cannot be fixed. Consequently, complete resurfacing of the fiberglass is required. So if your pool remained the same blue for the first day of its life then it is not a manufacturing issue. Keep in mind that this issue is very unlikely.

Don’t Drain or Acid Wash a Fiberglass Pool

DO NOT drain or acid wash your fiberglass pool – ever!  This is because very often any calcium buildup on fiberglass pool is not removed using this method.  However, if you insist on draining, we suggest using a licensed and insured professional. Remember, your pool walls must be properly cross-braced and secured to prevent buckling, cracking or warping when your water is released.  Finally, if your empty pool and is forced upward through hydrostatic ground pressure, you’ll need the contractor’s insurance to pay for a new pool. Remember, you cannot simply push the pool back down if uplift occurs.

Pool walls buckle inward from ground pressure. Photo credit: APCO Pool Specialties
Pool walls buckle inward from ground pressure. Photo credit: APCO Pool Specialties
Swimming pool pushed upward while empty. Photo Credit: Pool Water Recycling
Swimming pool pushed upward while empty. Photo Credit: Pool Water Recycling

OPTION 1 – Calcium Removal DIY kit

What We Do 1

FREE DELIVERY

Calcium Stains in Swimming Pools The Pool Stain Removers 3

7.7 lbs OF POWDER COMPOUND

Calcium Stains in Swimming Pools The Pool Stain Removers 5

CALCIUM DISSOLVING LIQUID

INSTRUCTIONS


  • 1 bottle (64oz) of our calcium prevention formula
  • 7.7 lbs of our granular calcium stain dissolving compounds
  • Phone support from our technicians
  • Simple step-by-step instruction video included
  • Pool does NOT need to be drained
  • Kit is shipped and tracked by FedEx
  • Kids are back in the pool in just 7 days
  • Kit is $295 for pools over 12,000 gallons

$245.00 (inc. Tax & Shipping)

Enquire now!

OPTION 2 – Calcium Removal – On Site Technician

TECHNICIAN VISIT

Calcium Stains in Swimming Pools The Pool Stain Removers 3

7.7 lbs OF POWDER COMPOUND

Calcium Stains in Swimming Pools The Pool Stain Removers 5

CALCIUM DISSOLVING LIQUID

TEST WATER


  • 64oz of our powerful calcium prevention formula
  • 7.7 lbs of our granular calcium dissolving compound
  • Complete 7 point on site water testing
  • Your pool does NOT need to be drained
  • Kids are back in the pool in 7 days
  • Visit is $405 for pools 12,000+ gallons

$405

Enquire now!

How fiberglass pools are made

This short video shows the construction process followed to make a fiberglass pool shell. Notice how thin the topcoat is that is first sprayed onto the mold.  This sprayed surface becomes the inside (or wet side) of your pool when it is finished. This is why it is important to maintain your pool water chemistry.  Likewise, the thin layer is exposed to the water, heat and elements all year round so take good care of your pool.  Remember, this thin surface can be damaged by neglect.  Finally, the outer layers of fiberglass are added throughout the process only to provide structural stability.

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