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Mold. Every spa owner's least favorite word.
If you've spotted the dreaded mold in or around your spa jets, perhaps you've left your hot tub a little too long without a water change, or maybe you've had trouble maintaining your sanitizer levels.
Whatever the reason, it's important to deal with the problem ASAP.
In this article, I'll help you identify which type of mold you're seeing, and what you need to do to get rid of it.
Types of hot tub mold
Green, yellow, white, black... none of these are colors of substances you want to find in your hot tub water.
Here's a color-coded guide to help you identify what kind of mold you're looking at:
|Color||Type||Symptoms to look for|
|Green||Green algae||Green cloudy water and fuzzy growths|
|Yellow/brown||Mustard algae||Yellowish green water and yellow/brown growths|
|Black||Black algae||Hard black spots or flakes on the surfaces of your spa|
|White||Scale or white water mold||Hard flakes, or a slimy/papery substance if mold|
|Greenish/off-white||Biofilm||Slimy substance floating or growing on surfaces|
Before we get to treatment methods, it's also important to understand where the problem is.
Do you see mold around your hot tub jets?
If you have visible mold on the outside of your hot tub jets, it means your water is not properly sanitized, and has created conditions where the mold or algae was able to grow.
The good news is you can remove most types of visible mold fairly easily with a cloth or soft brush.
However, visible mold is often only the surface of the problem.
Is there mold inside your hot tub jets?
Maybe your water is green or cloudy, or perhaps you've drained and refilled your spa with fresh water, but the water gets dirty again within an hour.
If you can see mold in your spa or around the outside of your jets, unfortunately this means it's also well established inside the jets—and in the plumbing lines too.
No amount of cleaning the shell will get rid of this hidden mold, so you need a special type of cleaner to deal with mold in these hard-to-reach locations.
How to treat mold in hot tub jets and pipes
Once you have signs of any type of mold in your spa, it's always a good idea to change out the contaminated water and give your spa a fresh start.
Before you start the drain-and-refill process though, you'll want to use a jet and pipe cleaner. This is the only way to dislodge and kill any mold growing inside the plumbing lines.
Here's the most effective method I've found to do that:
The best cleaner for hot tub jets
Ahh-Some Hot Tub/Jetted Bath Plumbing & Jet Cleaner is an industrial strength pipe and jet cleaner.
It works by removing mold and algae from the inner surface of your pipes, forcing it out of the jets and into the tub, where it can be attacked by your sanitizer and removed with a skimmer or vacuum.
The result is a sparkling clean spa, both on the parts you can see, and the parts you can't.
How to clean mold out of spa jets with Ahh-Some
- Shock your water to raise the sanitizer to a very high level
- Add about 1 tablespoon of Ahh-Some gel per 300-350 gallons of water
- Remove your filter and let it float in the main body of the spa
- Run the pump(s) on high to circulate the water, with the air intake valve(s) open
- Run the jets and blower if equipped up to 30 minutes (a layer of dirty foam will form on the surface—that's all the contaminants coming out of your pipes!)
- Wipe the hot tub clean during this process, scraping, brushing or wiping any gunk off the jets and interior finish
- After 30 minutes of circulating the water, drain the spa, and wipe down the shell with a diluted bleach cloth (check carefully for any remaining spots of mold here—you need to remove the roots, or it could grow back easily)
- Rinse with clean water, and drain any water that accumulates from rinsing
- Bonus: use a wet/dry shop vac to suck/blow out any water left in the pipes
- Rinse your filter with clean water and reattach it in its casing
- Refill your spa with fresh water!
In severe cases where the water is very dirty, you may need to repeat the above process more than once.
Here's a demo of Ahh-Some in action:
And that's it! Simply repeat as part of your regular drain-and-refill schedule every 4-6 months, or whenever you notice signs of mold in or around your jets—or anywhere in your hot tub.
Is mold in hot tubs dangerous?
While most types of spa mold are not usually harmful to humans, mold does not look or smell good (which makes for an unpleasant soaking experience) and it can also clog your hot tub's filter and other equipment.
And as it does harbor bacteria, it can also cause allergic reactions, respiratory infections or other irritations in extreme cases.
That's why it's important to get mold treated—to avoid putting your family at risk, or causing damage to your hot tub.
How to prevent mold in hot tub jets
It's one thing to deal with the current mold situation, but you also want to prevent it from coming back.
Here are our top tips for keeping your spa sparkling clean and mold-free at all times:
- Shock and sanitize your water properly:
- Keep your filter clean with a regular cleaning schedule.
- Maintain a healthy water balance:
- pH between 7.2 and 7.8
- Total alkalinity between 80 and 140
- Calcium hardness between 150 and 250
- Consider using an algaecide like Leisure Time Spa Enzyme to destroy any algae as it forms. This won't fix severe cases, but can help keep things in check if you seem to experience frequent algae blooms.
- Keep the cover on when not in use. Whenever your spa is open, that's an opportunity for contaminants to get in and start forming mold or algae.