How to Remove Scale from a Fiberglass Resin Spa

What You'll Need
Rubber gloves
Plastic buckets
Gentle scrub
Multipurpose spa cleaner/White vinegar/Muriatic Acid
Lots of water

Fiberglass resin spas are the perfect way to enjoy the luxury of a spa from the comfort of your home. These lightweight spas can be installed in any home and the best part is that they are not prohibitively expensive. However, when you use a spa on a regular basis, you need to ensure that regular maintenance is carried out on the spa as well. Without proper maintenance and cleaning, the buildup of scale and algae can not only degrade the appearance of your fiberglass resin spa, but also affects the quality of water. 

The bad news is that removing scale deposits from a fiberglass resin spa without damaging the surface is not very easy. If you are having a problem with scale deposits in your spa, read on to find out how you can go about removing scale from a fiberglass/resin spa. 

Step 1 – Drain the Spa

The first step is to drain the spa of all water. Removing scales from a fiberglass resin spa will involve manual labor; so it is a good idea to slip into something comfortable that you don’t mind getting wet in. 

Step 2 – Use the Multipurpose cleaner

Scales are caused due to deposition of minerals from the spa water. Depending on the types of minerals that caused the buildup of scales, you may have to try different tactics and cleaners to remove the scale from your fiberglass resin spa. There are many multipurpose spa cleaners specifically formulated for fiberglass resin spas available in the market. These should be your first weapon in the war against scales. Follow the manufacturer’s instructions and apply the cleaner generously to a sponge and then scrub off the scales. Do ensure that you use a multipurpose cleaner that is specifically formulated for fiberglass resin spas, otherwise you could end up damaging your spa. 

Step 3 – Removing Black Scale

If you notice any black colored scale, this is probably caused by a buildup of minerals and mold. This will be mostly concentrated around the water jets. To remove this, fill refill your spa with water, add 5 cups of white vinegar to the water, and turn on the water jets. Do this for approximately 20 minutes and you should see the black scales falling off. 

Step 4 – The Last Resort

If the multipurpose spa cleaner and white vinegar are not enough to defeat the stubborn scales, there is one last weapon up your sleeve—muriatic acid. Mix a solution of 10 parts of water to 1 part of muriatic acid in a plastic bucket. Wet a sponge of scrub with this solution and use it to clean off the scales. Remember to use a glove at all times and avoid getting the acid onto your bare skin. Do not increase the concentration of the acid, otherwise you may damage the surface of your fiberglass resin spa. 

Step 5 – Rinse It Off

Once the scales have been removed, all you have to do is rinse off all traces of the cleaner/vinegar/acid and your spa will be as good as new.