If you’re a hot tub owner for any extended period of time, odds are you will encounter all manner of issues that will need troubleshooting. One of the more commons ones is cloudy hot tub water. Water that is grey, murky, hazy, or anything short of crystal clear all fit under this umbrella term. There are usually a few causes of murky water and we’ll break down each so you know how to identify and prevent cloudy hot tub water in the future.

Water Chemistry

I know we hammer this point home constantly at Hot Tub Warehouse, but it’s true. Keeping your water correctly balanced is the first thing you should be sure of as a hot tub owner. Test your water weekly, more if you are using your hot tub more heavily.

When you test your water, you should be paying attention to a few things: sanitizer, pH, alkalinity, and calcium hardness. Having excess calcium in the water (made noticeable by a high calcium hardness or total hardness reading) could be the reason you have a murkiness problem.

The Fix

You can counteract high calcium hardness by lowering both the pH and alkalinity, but most often a high reading means the water needs to be refilled. If your readings all seem correct across the board when you test your hot tub water, the problem may lie elsewhere.

Dirty Filter

If you’re sure your hot tub water is properly balanced, it’s time to check your filter. Hot tub filters that are clogged or dirty have a harder time filtering out small particles that may end up leaving your water cloudy and unclear.

The Fix

Cleaning your filters monthly should become a regular habit in your hot tub maintenance routine. The build-up gets absorbed in the material and needs to be eradicated for it to function the right way. The best way to do this is by removing the filters monthly and cleaning them properly by spraying them off with a garden hose (with a filter specific attachment, preferably) and soaking them in filter cleaner before letting them dry and returning them to the filter compartment. Filter cleaner strips the material of any built-up grease and scum that may not get removed with a filter alone. Many owners will have two separate filters and rotate them out while one is being cleaned. Dirty filters can be to blame for poor filtration, unbalanced water, and other complications. Filters should be replaced annually, less often if you rotate between two separate filters and if they’re maintained well.

A clean filter should trap any errant particles that are big enough to be trapped in the fibers of the filter. If this doesn’t work, you may need to refill your hot tub altogether.

Refill the Tub

A hot tub refill is sometimes the only way to fix cloudy hot tub water. However, as you drain and refill your hot tub you may realize that the problem originates in your fill water which could be very mineral rich.

The Fix

If you think this may be a problem, try testing the fill water for total hardness before filling. If this is the case (or if you just want to save yourself some time when balancing the water), try using a hose pre-filter. Pre-filters attach to the end of the hose and do just that—filter out the minerals that would otherwise be deposited in the water and clog up the hot tub filter. It may turn out that this was your major issue and you’ll have less cloudy hot tub water in the future.

Using a Clarifier

Clarifiers like Spa Pure Clarifier are an additive that you can use either during your normal maintenance routine or as a solution to cloudy water problems. If you’ve gone through the first three steps and haven’t been able to fix your murky water, try a clarifying agent in your hot tub water.

Clarifying agents work by bonding together small particles that are too fine to get filtered out on their own. Once a few of the particles stick together, they are much easier to be taken out of the water’s circulation.

In general, it’s recommended that you use a clarifier once a week as part of your regular maintenance schedule, particularly if your water is prone to becoming cloudy. Follow the manufacturer’s instructions on the bottle. With a liquid clarifier, you’ll generally add 2 oz. per 500 gallons of hot tub water as part of a weekly routine. If you’re trying to eliminate a serious murky water problem, double your dosage. Unlike a hot tub shock, you can use your spa immediately after adding a clarifier. Clarifying chemicals are compatible with most sanitation systems (bromine, chlorine, and biguanide).