Foamy & Cloudy Spa Water


The water in a spa may appear cloudy, when the jets are on high. Small whitecaps of larger bubbles on the surface is normal, as shown in the picture on the left. But, if you have larger volumes of foam, especially in an off-color, or the spa water is cloudy or hazy when the jet pumps are off - there is a deficiency (of sanitation or filtration) or a contamination.

No one likes foamy or cloudy spa water - this post will give you the action steps to take to restore water clarity in a spa or hot tub.

Check the Filter

Your spa cartridge filter could be due for a cleaning, so at first sign of hazy spa water, pull out the filter and give it a good cleaning with the garden hose. If you haven't done so in 6 months or so, use a spa filter cleaner to remove oils and minerals that can clog the pores of your cartridge filter. For best results, allow the cartridge to dry fully before using, or keep a spare on hand for a quick spa filter change. When you reinsert the spa filter, make sure that it is fully seated into the cartridge housing. Water can bypass a spa filter cartridge that is not inserted fully, or sealed up on both ends. Finally, if your cartridge is over a year old, it may be time to buy a new spa filter.

Check the Water Balance

Having the pH and Alkalinity in the correct range is important - it allows your sanitizer (bromine or chlorine) to be most effective at breaking down organics and inorganics in the water. As you test your water balance, also check your level of sanitizer in the water. You need a constant level of sanitizer in the water, to keep it from becoming hazy. After your chemical checks and balances are made, you may decide to shock the spa. In many cases, a clean filter and a good shocking of the spa will clear up cloudy or foamy water issues.

Check the Pump

Your filter pump, is it circulating water, or could it have an air leak or an air lock? An air leak into the pump will reduce the volume of water being filtered and circulated and an air lock will prevent any water flow at all. Air locks are common after draining the spa, and can be released by loosening the union nut on top of the pump, just until water begins to leak out, then tighten again quickly. If the pump is not operating at all - check the circuit breaker and any GFI outlets that may be tripped. Also check that the time clock is set-up properly to run the pump long enough each day for all of the water to be filtered once or twice.

Clean the Pipes

Spas and hot tubs can develop a slimy bio-film inside of the pipes, manifolds and hoses - behind the spa shell. This can build-up to levels where it breaks off from it's colony and becomes free floating. In cases where draining the spa does not solve a problem with cloudy or foamy spa water, with the other checks above completed, you likely could benefit from using a spa pipe cleaning product like Spa Rinse. Just add it to the spa a few hours before draining - you'll be amazed at the gunk this stuff removes. You can see it, as it is removed and floats to the surface. Yuck!

Drain the Spa

If you've not drained your spa in several months, the cloudy and foaming spa water could be sending you a message. Solids build-up fast in a spa, especially for one that sees frequent use. Depending on how much your spa is used, and by how many people will regulate how often it needs to be drained. For many hotel/motel spas, a weekly draining may be appropriate, and for home  hot tubs, every 3 months is usually adequate. Here's a handy formula to use to compute how often to drain the hot tub.


(Those are division signs, not plus signs!) For my hot tub, it works out to about every 111 days, or about every 3 months. Replacing the water regularly will help to prevent cloudy and foamy water, bio-film build-up, and reduce the workload for your spa filter and spa chemicals.

If it's been awhile since you drained the spa, you may save some steps and just drain and refill. You may still need to check the pump and filter, water balance and sanitizer level, but sometimes, draining the spa is the best cure for cloudy and foamy spa water.

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