If you own a hot tub or are planning to purchase one, there is an issue you will have to deal with at some point, cloudy water. Whether the water in your tub has just lost its sparkle or is so milky you can’t see the bottom, it is a problem you will have to deal with. If you go to a “big box” store for advice, they will suggest every chemical under the sun to fix your problem. One of these chemicals will be a clarifier.
Clarifiers are a good start to clearing your water but in my opinion not a permanent fix. As a spa service professional, my advice would be to find out why the water became cloudy and find a solution to that problem. At a “big box” hot tub dealer their solution is to sell you as many chemicals as you can carry, and if that doesn’t work, come back and buy more. Chemical clarifiers may clear your water briefly, but there is still an underlying problem that exists.
One problem may be as simple as the spa is out of sanitizer. In this case, raise your chlorine or bromine level and add a dose of the clarifier. In this case, I would recommend using the clarifier. You found the underlying problem, solved it, now the clarifier can clear the water. Another problem that can cause cloudy water is a dirty filter. This again is a simple problem to fix. Clean your filter.
I recommend cleaning the filter at least once a week for heavy usage. If you are only using the hot tub once or twice a week, then cleaning the filter every two weeks will suffice. After cleaning the filter, go ahead and add a clarifier. Again, you’ve found the problem and solved it. Now the clarifier can do its job.
I’m not a big believer in adding lots of chemicals to cure all water problems. A clarifier will almost always clear the water in your spa for a short time. The key is to find the underlying problem or the water will turn back to cloudy again. If the reason why the water turned cloudy is found it will save you time and money wasted on chemicals.
If your hot tub is so cloudy or milky you can’t see the bottom, don’t waste your time or money trying to clear the water chemically. Find out what caused the water to get that bad, fix the problem, drain the tub and start over by re-filling the tub.