Nothing stops you from enjoying your hot tub faster than hot tub scum. Whether the gunk is coming through your lines, gathering to form a ring along the acrylic, or just seen floating on the surface of the water, hot tub scum is an unpleasant buildup problem that typically signals that your sanitation can’t keep up with what’s being introduced to the water. Whether you’re preventing it from becoming a problem in your water or trying to eradicate it, we have plenty of tips about hot tub scum.

 

PREVENTION TIPS

Institute a Shower First Rule

Much of what makes up the greasy gunk of hot tub scum is brought in by bathers. Body oils, lotions, deodorants, and hair products all come off of hot tub goers’ skin and can be hard to filter out of the water. If you take a few minutes to shower off beforehand (and encourage this in hot tub visitors as well), you will get off all of those excess creams and skin cells before they start circulating in your spa water (and gumming up your filters). Showering before using a hot tub is a good way to prevent all kinds of water chemistry woes.

Water Balance

This is the most important way you can prevent any scum problems in your spa water—keep your water chemistry balanced. You should be testing your hot tub water a minimum of once a week to maintain proper pH, alkalinity, total hardness, and sanitizer. Test more often and adjust as necessary during times of heavy use.

Hot Tub Cleanliness

Keeping your hot tub clean can be easier said than done; some processes are a little time consuming. However, if you want to use your hot tub regularly and without scummy issues, it’s worth it to stick to a hot tub cleaning schedule in addition to adopting some good habits. If you have a mild scum problem, you may be able to wipe away any scum buildup or clean around the waterline without having to empty it entirely.

Emptying your hot tub every 90-100 days can be a good way to make sure you don’t develop scum problems (or to reset the system if you can’t get it to go away). Oftentimes, scummy buildup will be inside the pipes so you’ll want to always use a system flush cleanser the night before you empty your hot tub. When the water has been emptied, use a non-foaming cleanser to wipe down the acrylic shell before refilling. Cleaning the hot tub thoroughly when it’s empty is a good way to help your water chemistry stay balanced during normal times of use.

Shock Your Hot Tub

Shock treatments in your hot tub are something you should perform regularly, typically once a week in addition to immediately after instances of heavy use. Doing regular shock treatments will boost your sanitizer levels and break down organic waste that may otherwise lead to hot tub scum. You can shock your hot tub with a non-chlorine shock as well as a DiChlor shock system, whichever works with your current sanitizer system.

TYPES OF SCUM

Brown Scum

A common scum is of the brownish grey variety. This scum could be a mineral like iron reacting in your water or an indicator that your pH level is high. Try using a pH decreaser in the water and see if it resolves itself. If you have this scum reoccur on a regular basis, keep your pH balanced at the lower end of 7.2-7.4 for a few months and see if that resolves the issue.

Green Scum

A green scum in your hot tub is a sign of metal in the water. Copper, magnesium, or other dissolved metals in the water react with bromine and can leave behind a green residue. If you think it might be a problem associated with metals in the water, try using a pre-filter. Pre-filters attach to your garden hose so when you’re refilling your hot tub, 99% of contaminants and suspended solids are removed from your fill water so you won’t have to compensate later when balancing your water.

Blue/Green Scum

If your hot tub scum has a bluish green tint, there’s a chance you have a filter problem. Whether it’s clogged, torn, or worn out, this is where you should spend your attention. Remember: standard cartridge filters need to be changed every 1 ½-2 years, depending on how they’re maintained. To clean a filter, spray with a hose and use a filter cleaner. Let it dry completely before replacing in your hot tub. If there are tears in the fibrous material or it looks dingy and worn, replace it altogether. This may help with your scum problem.

Other Treatment Options

If you need some additional ideas for maintaining scum, there are a few other products that will help keep your water scum-free:

Floating sponges (Swimline GooGetter, Scumball)—These products float in the water and absorb things like lotions and oils that may have sloughed off bathers and gotten in your water. These products are inexpensive and the GooGetter can absorb up to 40 times its weight in body oils and lotions. Once it has become full with gunk, you can squeeze it out (wear gloves!), wash it, and reuse it. The Scumball comes in a pack of two and needs replacing every 30 days.

Water Clarifier (Spa Perfect, Leisure Time Enzyme, Spa Pure EZ-Enzyme)—products like these that are enzyme clarifiers which break down organic waste to basic elements like carbon dioxide and water and are then absorbed into the spa/hot tub environment. This can be added to your water on a weekly basis.

Stain and Scale Preventer (Spa Pure Stain & Scale Preventer)—This product eliminates scale and minerals that may contribute to a scum problem. It softens water and helps prevent minerals like copper and iron from getting deposited in the water. This too can be added every week.