Got a Nasty Yellow Ring Around Your Hot Tub? There's a Simple Fix

Jennifer Rhodes

By Jennifer Rhodes · Updated

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If you've noticed a yellow ring around your hot tub, don't panic! In most cases, this is simply due to a buildup of oils brought into the spa on your skin over time. However, if the ring is resistant to cleaning, it may be caused by calcium deposits.

In this article I'll run you through how to fix both cases, and give you some tips to avoid the problem coming back.

What causes a yellow ring around a hot tub?

There are a few different things that can cause a yellow ring to form around a hot tub.

Body oils

The most common is scum, which basically means a buildup of oils (think sweat, makeup, lotions, or hair products) which can come off of our bodies when we enter the spa.

These substances collect on the surface, which can then lead to a yellowish ring when they collect around the edge at the waterline.

If you can wipe the yellow ring away fairly easily, you have a scum buildup.


Another possibility is that the hot tub is filled with hard water and scale has started to form. If calcium and scale build up around the edge of the tub, it can also cause a yellow or whiteish ring—as well as a sandpapery feel elsewhere in the tub.

In this case, you could also have problems deeper down in your spa's parts because scale is likely covering those as well. We want to avoid these getting clogged with scale at all costs.

If the ring is hard, rough or abrasive, it's most likely calcium.

How to eliminate scum lines

There's a simple fix for yellow scum lines: an oil-absorbing sponge.

Oil-absorbing sponges are a cheap and easy way to keep oil problems at bay. These are special hydrophobic sponges, which means they absorb oil but not water.

They sit in your tub and attract any oil towards them. You usually place or tie them in your skimmer, which means they're mostly out of sight.

What's the best oil-absorbing sponge?

There are two main contenders for the best oil absorbing sponge on the market, both of which are available on Amazon. There's the Scumbug which is great for removing oil and comes in a cute bug shape:

Scumbug Oil Absorbing Sponge, 4 Pack
Scumbug Oil Absorbing Sponge, 4 Pack
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The second option is the Scumball which works the same way, but it's more of just a regular ball shape:

Horizon HV-SB2PK Scumball Pool and Spa Scum Eliminating Ball (2 Packs of 2)
Horizon HV-SB2PK Scumball Pool and Spa Scum Eliminating Ball (2 Packs of 2)
View on Amazon

Another option that some hot tub owners swear by is the Mr. Clean Magic Eraser. It's a popular cleaning tool that can be used on a variety of surfaces:

Mr. Clean Magic Eraser
Mr. Clean Magic Eraser
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Any of these should take the yellow ring off, but not harm the shell of your hot tub. You can also just use a microfiber cloth to wipe away the ring for now if you can't get an oil-absorbing sponge right away.

How to eliminate calcium lines

Calcium lines are a little harder to deal with. This is because in addition to the ring, every surface underneath the water in your spa will also be covered with scale. This means every component of your plumbing system, including your pumps, jets, and spa shell surface. Because it is abrasive, it can harm all of these parts.

The easiest solution to this problem is vinegar. Calcium can be dissolved by acid, and vinegar contains acetic acid.

Buy two or three gallons of white vinegar and pour it into your spa:

Heinz Cleaning Vinegar, 128 Fl Oz
Heinz Cleaning Vinegar, 128 Fl Oz
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The scaling should disappear after 24 hours. You'll want to drain and refill your spa after this because the pH of the water will be too low.

Then monitor your calcium hardness levels more carefully next time, and try to keep it between 150 and 250.

If you live in an area with especially hard water (and your calcium hardness measures above 250 ppm), you can try a scale control product which should help to keep the problem at bay:

Leisure Time 30210A Defender Spa and Hot Tub Stain and Scale Cleaner, 32 fl oz
Leisure Time 30210A Defender Spa and Hot Tub Stain and Scale Cleaner, 32 fl oz
View on Amazon

Preventing the yellow ring from coming back

There are several things you can do to prevent the yellow ring from coming back:

  • Make sure you're entering the hot tub as clean as possible (shower before every time if you can)
  • Clean the filters regularly to prevent any oil building up here
  • Get a Scumball, Scumbug, or Magic Eraser
  • Maintain the correct water balance—especially calcium hardness

By following these simple steps, you can help keep your hot tub clean and free of any unsightly yellow ring.

Closing thoughts

If you have a yellow ring around your hot tub, it's likely due to a buildup of either body oils, or minerals in the water.

This can be caused by introducing oily substances, using hard water to fill your tub, or by not properly maintaining your water balance.

To get rid of the yellow ring, you'll need to clean your tub with either an oil-absorbing sponge if the problem is a scum line, or an acidic cleaner like vinegar in the case of calcium deposits.

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