How to remove hard water stains from fiberglass tub

Fiberglass tubs are attractive and durable but often end up with undesirable stains. Hard water stains form on the tubs due to the accumulation of minerals such as magnesium and calcium. These deposits can make your tub look dirty and unappealing. 

Getting rid of any stains immediately will prevent the deposits from building up and becoming harder to remove. Luckily, you can remove hard water stains from a fiberglass tub with some household products at home. Read further to learn ways on how to remove hard water stains from fiberglass tub.

Techniques on how to remove hard water stains from fiberglass tub

Once you spot hard water stains on your fiberglass tub, you must remove them right away. Let us take a look at several methods on how to remove hard water stains from fiberglass tub using several common household products. 

Baking soda paste

Baking soda works like a natural abrasive that will not damage the surface of the fiberglass. 

  • Mix an equal amount of baking soda with water or white vinegar to create a thick paste. 
  • Dab this paste on the tub and gently rub over the hard water stain.
  • Leave it in place for 10-15 minutes and wipe it away using a soft sponge or a nylon brush.
  • Reapply the paste until the stains are completely removed. For stubborn stains, leave the paste overnight. 
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White distilled vinegar

Vinegar works by breaking down the mineral deposits. This will allow you to wipe them away easily. 

  • Saturate paper towels in white distilled vinegar. Place them directly onto the hard water stains. 
  • Leave in place for up to 30 minutes. 
  • Rinse the tub with cool water to get rid of any traces of vinegar. 
  • Use a non-abrasive sponge to scrub on the stains along with liquid dishwashing soap until they are completely removed. 

Commercial cleaners

You can find commercial cleaning products in stores that can remove hard water stains as well as keep your fiberglass tub clean. Make sure that you will check the label to decide if they are effective in eliminating hard water stains.

Some household all-purpose cleaners, soft scrub products, and bathroom cleaners are effective in removing stains. Make sure to test the cleaning products in a concealed area first. 


Important considerations when cleaning a fiberglass tub

When cleaning a fiberglass tub, avoid using any harsh abrasive cleaners to get rid of hard water stains. Remember that these cleaners can dull the finish of a fiberglass tub and can even scratch the surface. 

Soft-bristled toothbrushes and non-abrasive sponges work best in eliminating hard water stains since they will not scrape the fiberglass. 

Make sure that you will dry the tub after every use to prevent the formation of hard water stains. After cleaning the tub, polish it with a whitening polish and a soft cloth.

Can you use vinegar to remove water stain from fiberglass tub?

Fiberglass is a commonly used material for bathtub and shower surfaces. This is a long-lasting material and requires basic care and maintenance to preserve its appearance. Sadly, if you have hard water, stains will steadily build up on the surface of your fiberglass tub. Let us take a look at the steps on how to deal with water stains on your fiberglass tub.

  • Fill a spray bottle with undiluted white vinegar. 
  • Spray over the surface of the fiberglass tub. Allow it to soak the stains for 10 minutes to loosen them.
  • Saturate paper towels with vinegar and wrap them around the faucet of the bathtub to loosen the hard water stains and any mineral deposits. Leave the saturated paper towels for around 10 minutes and discard it after. 
  • With a clean sponge, saturate it with vinegar. Sprinkle baking soda on one side of the sponge. Scrub on the stained areas of the fiberglass bathtub. Utilize the combination of vinegar and baking soda to clean the rest of the tub. 
  • Rinse the bathtub with water. Use a clean cloth to dry the fiberglass surface. 
  • Polish the sides with olive oil to avert the formation of hard water stains in the future. Utilize a dry cloth or towel to wipe away the excess oil to prevent it from becoming slippery. 
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Can I use CLR on my fiberglass tub?

If you have a fiberglass tub at home, you can use CLR to clean it. The product is considered safe to use on fiberglass material. Start with a mixture of CLR and water and later on progress to full strength if necessary. 

When using CLR, the area must be properly ventilated and wear gloves. Combine equivalent amounts of warm water and CLR. Do not forget to try out the solution on a concealed site before it is applied to the entire surface. 

Apply straight to any calcium, lime or rust mark using a cloth, brush or sponge and wash away immediately with cold water. Do not leave it in place longer than 2 minutes. 

In case the stain lingers, use CLR in full strength and wipe and rinse immediately with cold water. Remember not to combine CLR with other household cleaners or bleach. 

Can you use Magic Eraser on fiberglass tub?

For some, they have used Magic Eraser on fiberglass surfaces, but a piece of good advice to remember is to avoid rubbing too much or too hard. 

It is important to note that Magic Erasers are abrasive. With this in mind, avoid using one on delicate countertops such as granite or marble. If you are going to clean a fiberglass tub, remember that it is vulnerable to scratches. 

Final thoughts

When your fiberglass tub ends up with hard water stains, you should remove them to prevent the stains from becoming difficult to remove. Make sure that you will use the appropriate cleaning products and tools to prevent any damage to your fiberglass tub. With the methods discussed on how to remove hard water stains from fiberglass tub, you can easily get rid of hard water stains in no time. 

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