Getting that horrible, oily scum line around your hot tub?

Look's pretty disgusting, right?

We all get a bit too relaxed with our chores sometime... so even if you've been really diligent with keeping your hot tub clean and checking your water quality, your spa can still develop some oily scum on the shell around the waterline, or on the water itself.

The important thing is to know what the causes are, so you can remove it and prevent it from reoccuring.


What causes hot tub scum lines?

A fair amount of what goes into your hot tub's water is removed by your filter. Dust and debris, nasty chemicals and even bacteria. But a filter isn't magic... it can only do so much, and for so long.

If the contaminants that find their way into your hot tub water are left for long enough, or if you've not taken the appopriate measures to combat them, eventually they will form a nasty layer of scum that will float on the surface of the water and form a horrible ring around the shell, which looks really unappealing!

1. Bodily residue

OK, we know it sounds a bit disgusting, but it's natural. This is one of the most common causes of scum in a hot tub.

Every day, our bodies rid themselves of 30-40,000 dead skin cells. That process is accelerated by sitting in bubbling hot water.

We also lose up to 100 hairs a day, and the human body produces oils that will rise to the surface of the skin. Even though you're sitting in water, it's usually much higher than your body temperature meaning you'll sweat whilst you soak.

As soon as you climb into your hot tub, a lot of these contaminants will end up in the water with you.

2. Personal care products

On top of the things that our bodies shed naturally every day, we also add a lot of products, such as:

  • Deoderant
  • Perfume
  • Shampoo
  • Aftershave
  • Skin Lotions
  • Make-up

...and pretty much everything and anything else that you might use to make yourself look, smell and feel so fabulous!

These products end up in your hot tub water if you don't remove it with a quick jump in the shower before using your spa.

3. Metal in the water

We don't mean jewellery (though you should take that off, too!) - we mean the actual metals that are present within the water.

All water everywhere has at least trace amounts of certain metals such as iron, magnesium and copper. Depending on where in the UK you live, the concentration of certain metals might be higher in your area.

Once those metals start to react with the chlorine in your hot tub, they can oxidise and potentially cause a greenish scum to form in the water.

4. Bad water chemistry

Keeping the water in your hot tub sufficiently balanced is an essential part of keeping your spa clean and healthy. If your water is unbalanced - particularly if you have a high pH - you can create a welcoming environment for algae and bacteria... creating scum. 

Read our Ultimate Guide To Hot Tub Water Care

5. Dirty/worn out filter

The filter's job is to keep the water in your hot tub clean. It can't do that if it's dirty. Make sure to clean your filter regularly.

At some point, cleaning the filter won't be enough to keep it functioning effectively and it will need replacing.


Cleaning the scum lines

Now you know what causes the problem... let's fix it!

Click on the article below to learn how to effectively remove scum lines from your hot tub.



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