Pool and Spa Scum Lines: Prevention and Treatment

Scum Lines, one of the worst eyesores that can happen to our swimming pools and spas. Not only because it looks dirty (because it is) but it’s also yucky and slimy to the touch and it causes other debris to stick to it as well, compounding your problem even further. Scum lines are something that’s pretty much a norm for spa owners because of the limited space in the spa, leading up to higher concentrations of inorganic and organic waste, but to pool owners (especially those with larger than average pools), it takes a special set of circumstances to end up with a scum line problem.

What causes scum lines?

Scum lines are caused primarily by organic waste in the water. This can come in the form of natural body oils from bathers, oils from lotions and other cosmetics, animal waste, and other things that are basically not soluble in water. These types of waste are usually lighter than water so they tend to create a thin film on the top layer of your water. Once this layer of waste hits the sides of your pools, they will tend to stick to those surfaces, causing a visible line of scum to form.

Once a line has established then your scum line problem can easily spiral out of control because of its tendency to grab on to other floating microscopic debris, compounding the problem.

How to deal with scum lines?

While it may sound like a simple problem to fix, scum lines are actually pretty tough to remove once they’ve established themselves. It will take an extra-strength tile cleaner to fully remove scum lines. You’ll need to lower your pool water to below the existing line, spray on some scum/tile cleaner on the lines, allow around five minutes for the solution to “eat” away at the scum and get to scrubbing!

Preventing Scum Lines

There are a lot of ways to prevent scum lines from occurring in the first place and let’s look at them in more detail, shall we?

Using "Scum Catchers"

One of the best ways to prevent scum lines in your spa is to use a Life spa disc (or tennis balls if you have a bucket of them lying around, just make sure that they are clean). What this does is that instead of sticking to the sides of your spa, organic contaminants will stick to the spa disc or the tennis balls instead. This will save you a lot of time and effort in cleaning your spa surfaces and if the spa disc gets too dirty or saturated with grime, then simply chuck it out and get a rew one.

Using Enzymes to prevent scum lines

We’ve talked about enzymes in depth here and they excel in helping prevent scum lines like nothing else! They work in tandem with your chlorine to ensure that scum lines never happen. What enzymes do is break the nonliving contaminants down to manageable bits and chlorine finishes them off!

Scrubbing, Scrubbing, and more Scrubbing

This is the best way to prevent scum lines is to just stick to your regular pool maintenance routine and just keep on scrubbing. By religiously scrubbing your water lines on a schedule, you’re preventing scum lines from taking hold and snowballing out of control!

If scrubbing your pool water lines on a religious basis sounds like too much work and you’re regularly experiencing scum lines then your next best option is to get a robotic pool cleaner like the Tornax TX30. Robotic pool cleaners like the Tornax TX30 clean your water lines in its cleaning routine, scrubbing out scum and filtering it out even before it gets the chance to establish itself.

Keep your Filters in Top condition

Another way to prevent scum pool and spa scum lines is to keep your filters in top shape. You can use the Water TechniX filter cleaning solution on both sand filters and cartridge filter to melt away the existing gunk that regular cleaning doesn’t wash off, giving it more capacity to catch even more oils and other contaminants that cause scum.

Keep your pool free of Phosphates

One of the top causes of scum lines is heavy bather load and debris. This brings with it phosphates, which as we know is algae superfood. While phosphates do not directly contribute to scum line formation, it does give your chlorine a hard time in dealing with the contaminants that DO contribute to scum line formation since it will have to deal with increased algae growth. By removing phosphates, algae is starved and chlorine can have an easier time in dealing with scum-forming waste in your pool.

Showering Before Swimming

And probably one of the ways that we don’t think about when it comes to scum lines is to take a shower before taking a dip in our pools or spa. By taking a shower before swimming, we’re washing off all the organic debris like oils, dead skin cells, lotions, and other stuff, preventing them from entering the pool in the first place!


Yes, scum lines are annoying, and they’re very hard to take care of, but they’re quite easy to prevent. Simply shower before using the pool or spa and stick to your cleaning regimen and it should prevent the formation of scum lines. If this doesn’t fully prevent it, then some help from specially formulated enzymes designed specifically for scum line prevention would go a long way!

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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