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10 Reasons Why Your Spa Water is Cloudy

Do you have cloudy hot tub water? If so, you are not alone. Hot tub or spa water that is cloudy may be the number one water problem plaguing spa and hot tub owners.

There is a lot of misinformation out there about cloudy spa water, such as "Bromine will make your spa cloudy," or "Metals in the water cause cloudy hot tub water." There's also the ever-present sales pitch — if you just had this super-special magical water treatment, all your spa water problems will disappear! Right...

While the right chemicals will help correct the underlying issue, spa and hot tub water problems usually require a bit of diagnosing and troubleshooting first. If your spa or hot tub water is cloudy, hazy, milky or turbid, your problem is likely one of these situations below, or a combination of them.

fix cloudy hot tub water by balancing the water

1. High Calcium Hardness, Total Alkalinity or pH

Your spa water chemical balance may be to blame. Take an accurate reading of your Calcium Hardness, Total Alkalinity and pH levels. In areas where hard water is common, calcium can easily come out of solution and cloud the spa water. If your Calcium Hardness levels are greater than 300 ppm, use a sequestering agent to help control scaling, and use a chemical balancer to manage the pH and Total Alkalinity levels in your spa. This will help keep your spa water clear and prevent scaling and cloudy hot tub water.

If your test for Total Alkalinity (TA) shows high levels above 150 ppm, excess carbonates can come out of solution and make the spa cloudy. High TA levels will also make it hard to control your pH and keep it in range. Use pH decreaser to lower TA to around 100 ppm. If your spa pH level is outside the range of 7.2–7.6, adjust accordingly for easier control of cloudy water.

Total Dissolved Solids, or TDS, are usually not a concern in spas and hot tubs. But if you have not drained your spa in a long time, you could have high levels of dissolved solids in the water. When water reaches its saturation point, which means it can't absorb more solids, frequent bouts of cloudy water are to be expected. If your TDS reading climbs higher than 1500 ppm, it's time to drain and refill the spa.

2. Cloudy Fill Water

Maybe the problem is not with your spa, but in your fill water. Regardless, well-balanced and sanitized spa water with proper filtration should self-correct this situation, and you'll have clear water within a day or so. A spa clarifier can help coagulate suspended particles for easier filtration. In most cases, it may be better to use a spa pre-filter to remove particulates that cloud up spa water. Just attach it to your garden hose when adding water or refilling your spa or hot tub.

fix cloudy hot tub water by raising sanitizer levels

3. Low Spa Sanitizer Levels

Some people are sensitive to bromine or chlorine, and try to operate the spa with as little as possible. That may be OK if you have other sanitizers working, such as an ozonator or a mineral cartridge, and your water chemistry is balanced, particularly the pH level.

Otherwise, spas should always have a level of 4–6 ppm of bromine, or 3–5 ppm if using chlorine. When the sanitizer level drops below 1.0 ppm, foreign particles in the water run rampant, and organic contaminants grow faster than they can be destroyed.

A proper sanitizer level should destroy the particles that induce cloudy hot tub water. To give your sanitizer a boost, shock the spa water regularly. Be sure to shock the water after several people have used the spa, or if sanitizer levels suddenly drop to very low levels. If a chlorinated spa shock clouds your water, try using non-chlorine MPS shock instead.

4. Air in the System

Small particles of air or tiny bubbles can make the spa water appear cloudy. If your spa has bubbles coming into the returns, but your air blower and spa ozonator are turned off, you may have an air leak on the suction side of the pump. The suction side is anything before the spa circulation pump. A loose union fitting before the pump or a loose pump drain plug can pull air into the system.

Low water level in the spa can also bring air into the spa, giving the water the appearance of being cloudy or hazy. Inspection of the pipes and equipment before the spa pump can reveal the source of the air leak, which can then be fixed with sealants or lubricants.

fix cloudy hot tub water by cleaning the filter

5. Spa Filter Problems

This is a common cause of cloudy spa water. A hot tub or spa filter cartridge may be incorrectly positioned, allowing water to bypass the filter cartridge. Make sure the cartridge is fully seated on both ends to force the water to go through the pleated spa filter material.

A spa filter cartridge won't last forever, and each cleaning reduces its efficacy a little more. After about 15 cleanings, replace the spa filter, and you'll notice an immediate improvement in water clarity. Usage puts a toll on the filter, and for average hot tub usage, filters should be replaced every 12–24 months.

Spa filter cartridges can also become gummed up with oils or minerals, drastically reducing their filtration ability. These substances can be difficult to remove with a garden hose alone. Spraying or soaking a cartridge with spa filter cleaner before cleaning will break down greasy or crystallized deposits and restore full flow to your filter.

DE filters are more commonly used on inground spas, and if a DE filter grid develops a hole, it will allow DE filter powder to come into the spa. This will cloud the water and leave deposits of a light brown powder on the seats and floors of the spa.

6. Spa Pump Problems

hot tub pump

There are a number of pump problems that can lead to cloudy spa water, the first being the amount of time the spa filter is running each day. You may need to increase the spa pump run time to increase your daily filtration. Running a pump only on low speed can also contribute to ineffective filtration. We recommend running the pump on high for at least 2 hours every day.

Another issue could be with the spa impeller. It could be clogged full of pebbles, leaves, hair or any number of items. The vanes on a pump impeller are very small and can clog easily, which will considerably reduce the flow volume. Another possibility is a broken impeller. The pump turns on, but the impeller is not moving, which reduces flow rates to zero.

If you have no flow from your spa pump, there could be an air lock, especially if you have just drained and refilled the spa. To fix an air lock, shut off the pump, loosen a union on the pump, and allow air to escape, tightening it when water begins to leak. If the pump doesn't turn on at all — well, there's the source of your cloudy hot tub water problem. A non-working pump could result from a tripped GFCI button, loose wires, a bad contactor or relay, or another pump control issue.

Air leaks before the pump, as discussed above, also make the pump less efficient by reducing the total water volume. Water leaks after the pump are also a problem, in that your water level will soon drop below the skimmer intake, begin to take on air, lose prime and stop pumping your water through the filter.

leisure time jet clean

7. Biofilm Problems

Biofilm is a slimy bacteria that coats the inside of pipes and fittings. In extreme cases, it will cloud the water, and you may notice slimy flakes floating on the water, or have severe issues with spa foaming. Biofilm forms quickly in a spa that has sat empty and idle for some time. If you suspect a biofilm contamination, lower the pH to 7.2 and use spa shock to raise the chlorine level above 10 ppm. Follow this up with a treatment of Jet Clean to remove biofilm deposits. To prevent future buildup of biofilm in your pipes, try adding an enzyme product to your hot tub maintenance regimen.

8. Salt System Problems

Salt systems are becoming more popular with spa owners, although they are much more prevalent in swimming pools. The challenge with salt systems is that it is possible to place too much reliance on them, and never check the chlorine level. Spa salt cells need occasional cleaning to maintain chlorine output.

Adding salt to your spa when needed may temporarily cloud up the water, at least until the salt becomes fully dissolved. When adding salt, be careful not to overdose. Run the jets on high for greater agitation of the water.

9. Biguanide Problems

If you use a non-chlorine, biguanide sanitizer in your spa and have difficulty with cloudy spa or hot tub water, you are not alone. This is the main complaint of using a PHMB sanitizer. You may find relief by draining and refilling the spa, then changing the spa filter, which is probably gummed up with residue. Using spa chemicals with any amount of chlorine, or using algaecides or any other non-approved chemical, will not only cloud the water in a biguanide spa, it can create some wild colors, too!

10. Soaps, Lotions, Cosmetics and Hair Products

cloudy spa water

This problem is common for almost every spa, unless all hot tub users shower well before entering the water. Everything we put on our body and in our hair can end up in the spa, bringing oils, phosphates, detergents and a hundred other undesirable chemicals into the water. These can consume sanitizer, clog spa filters, and make the water cloudy and foamy. If your spa has a high bather load or is used as a giant bath tub, you can expect issues with water clarity. Adding spa enzymes can help control greasy gunk, reduce sanitizer demand, and lessen the clogging of your spa filter.

Cloudy spa water is not so difficult to find and fix, but remember that you may have more than one of these issues working against you. Consider each cause of cloudy spa water carefully. If you're dealing with cloudy water in your hot tub, it's likely one or more of the situations above. Don’t forget, draining the spa regularly is important to prevent cloudy water. Depending on how much the spa is used, draining it every few months is a good way to keep your spa water from becoming cloudy in the first place! If you have specific questions about cloudy water in your spa or hot tub, bring a water sample to your local Leslie's for a free in-store AccuBlue water test and customized water treatment plan.

Recommended Products

Leslie's Fresh N Clear Shock

Chlorine-Free Shock

Natural Chemistry Spa Perfect

Spa Water Cleaner

Leslie's Elite Replacement Spa Filter

Spa Filter Cartridges

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Leslie’s makes every effort to provide accurate recommendations based upon current ANSI/APSP/ICC-5 2011 (R2022) standards, but codes and regulations change, and Leslie’s assumes no liability for any omissions or errors in this article or the outcome of any project. You must always exercise reasonable caution, carefully read the label on all products, follow all product directions, follow any current codes and regulations that may apply, and consult with a licensed professional if in doubt about any procedures. Leslie’s assumes no legal responsibility for your reliance or interpretation of the data contained herein, and makes no representations or warranties of any kind concerning the quality, safety, or suitability of the information, whether express or implied, including, without limitation, any implied warranties of merchantability or fitness for a particular purpose.