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What to Do When Your Hot Tub Water Turns Hazy, Milky, or Foamy

Published by E-Z Test Pool Supplies on 05/15/2017

What to Do When Your Hot Tub Water Turns Hazy, Milky, or Foamy

What could be more inviting than a hot tub with clear, warm, bubbling and soothing water? Clear water, although not the only vital sign, is definitely a key part of healthy water. Symptoms such as cloudiness, haziness, or excessive foam point to problems in chemical balance, filtration and/or circulation in your spa. Sooner or later you may run into any of these problems, and so in this blog we’d like to talk about how to fix these symptoms. Here are the key questions we’ll tackle: What should you do when your spa water turns hazy? What can be done about milky water in a spa? Can anything be done to get rid of foam in your hot tub?

Hazy…cloudy…milky – these are all terms we use to describe water that is anything short of clear. Try not to think of these descriptive words as different conditions so much as the degree of lack of clarity that the water suffers from. I tend to think of hazy as the least of the three terms and milky as the highest degrees of lack of water clarity. The spectrum runs anywhere from a light haze to a dense, milky appearance.

Why is it cloudy?

These problems may be the result of dead algae, unbalanced chemical levels, lack of sanitizer, minute particles suspended in the water, or even problems with the filtration system.

Let’s address water that is cloudy or milky in appearance and talk about how to cure these issues. Here are some simple steps you can take to remedy the problem.

  • Examine, clean, or replace the filter cartridge(s) – This should ALWAYS be your starting point for cloudiness. Look for cartridges that are dirty, or have buildup of chemicals or scale. If this is a problem soak the cartridge(s) overnight in a filter cleaner and replace the next morning. If the cartridge is extremely discolored even after soaking, has pleats that are stuck together, or there are tears in the fabric, then it is time to replace the cartridge with a new one. In general most quality spa filter cartridges have a life span of about one year before they need to be swapped out.
  • Check your filter cycle times – It is best to consult your spa’s operator’s manual for run times, however running the filter on a continuous cycle from anywhere between 8 and 12 hours may help turn around a cloudiness issue.
  • Test water for chemical levels – Although testing at home with strips and drop-style kits is important, you may also want to bring your water to a spa and pool store that has the capability to test with professional equipment. Immediately adjust all chemical levels that are off, particularly sanitizer and pH levels.
  • Shock your hot tub – Shock your water with either granular chlorine or non-chlorine shock (if you do not use chlorine as your sanitizer). In the event of algae or organic debris causing problems, this will help to oxidize, or chemically burn up, the offending culprit and lead to clearer water.
  • Use a clarifier – Clarifiers work to coagulate and draw together particles that are too small to be caught by your spa’s filter. The result is larger particles that do not pass through the pores of the cartridge and are removed from the water. End result? Clearer water! Keep in mind that although clarifiers may be an effective solution, they should be used sparingly – usually using an ounce or two of most clarifiers is sufficient. Use too much and you may see the problem get worse!
  • If all else fails, empty the spa and refill – Filter cartridges, filter cycles, chemical balance, sanitizer and clarifiers will only go so far. It is for this reason that we recommend draining and refilling your tub every 3-4 months. The small volume of water in a hot tub relative to bathers, as well as the higher water temperatures which draw out more bodily oils, sweat, cosmetics and other pollutants accumulate over time. There is only so much that can be done to maintain clear water until a tipping point is reached and no amount of chemicals, filtration and run time will bring satisfactory results. At this point change the water!

As far as excess foam in your spa, this is usually a buildup of oils from the body, hairsprays, gels, deodorant, makeup, and detergents and a reaction of these oils with higher pH water. Also, low calcium hardness may exacerbate the appearance of foam in your hot tub. The main purpose of calcium hardness is to protect plastic, acrylic and other materials from water’s natural tendency to leach critical substances from these materials, thereby leading to breakdown. A side effect of low calcium hardness is often excess foam. So here’s how to eliminate foam.

  • Prevent foam from the very beginning! – Ask anyone using your hot tub to shower before using the hot tub. This will do quite a bit to wash away oils, deodorants and cosmetic buildup before getting in. Also, when laundering bathing suits take care not to use excess detergents. Using an extra rinse cycle is recommended when laundering bathing suits so as to minimize potential for foam.
  • Use enzyme based spa productsOnce again this is a pro-active solution, preventing the issue BEFORE it occurs. Many products for use in spas now employ enzymes, which naturally break down oils and contaminants which lead to foam. Because of the addition of these products there is less use of sanitizers such as chlorine or bromine. The end result is less chance for nuisance foam in the water. One such product is Spa Perfect™, which we carry and recommend at E-Z Test Pool Supplies.

  • Use a Foam Elimination Product – We carry Foam Away™ from N. Jonas Chemical Company. This product will completely rid your spa of nuisance foam in a matter of minutes in most instances and using only a few ounces per treatment. This product is only to be used after foam is a problem, but works quite effectively.

One Last Step to Try

  • Drain and refill tub – As with cloudiness issues this is a last resort If doing this, we suggest running a solution such as a jet-line cleaner to remove biofilm from the spa’s water circulation lines and prevent foam going forward.

If you have any questions or would like to learn more, our team at E-Z Test Pools would be happy to assist you! Visit us in-store or online at!