You’ve likely asked yourself how often to change my hot tub water? Just because the water still looks clear in your hot tub doesn’t necessarily mean that it’s still ok to use. There are a few factors that will determine how often the water needs to be changed. Learn more about this important aspect of spa maintenance and ownership. 

How Often Should You Change Hot Tub Water

The type of water that you fill your hot tub with will impact how long you can keep it in your spa. Soft water is better than city water which is better than well water. “Hard” water has a lot of calcium and magnesium in it, and soft water is treated water that has very little, if any, calcium and magnesium. Well water is typically hard, which is good for drinking, but not so good for your spa due to the minerals in it. 

As long as you treat the water in your tub properly, it should last a long time. Cheap chemicals leave behind solids which are inert ingredients like fillers, binders, glues, etc. These materials can cause cloudy water, requiring more chemicals and ultimately can cause you to have to change your water more frequently. Higher quality chemicals don’t leave behind these solids and you can use smaller amounts to get the job done.

Frequency of use will have the biggest impact on your water quality. A family of four using a hot tub a few times a week is going to transfer more extra material or “leave behinds” (skin cells, dirt, oils, residue, etc) than a couple using it once or twice a week. The location of your spa may also create additional challenges. Is it under trees? Did you forget to put the cover on? Is there mulch, dirt or gravel around it? Remember it’s the extra stuff in the water that causes problems.  

How Often to Change Hot Tub Filter

When you add chemicals, they add to the saturation of the tub’s water which will eventually reach a max point where they will no longer dissolve. As the water gets older and the total dissolved solids (TDS) rise and you will notice your filter may need to be cleaned more often as it’s trapping those partially dissolved solids which can reduce the energy efficiency of the tub’s heater. Buy a spa with a good filtration/purification system and avoid unnecessary stress on it by changing the water and filters when needed.  

Because hot tubs are kept very hot, this affects what you need to do to keep your water clean and clear. As the hot water evaporates, it leaves behind any added solids: chemicals, bather waste, etc which adds to the overall saturation of the water. A hot tub contains a much smaller amount of water than a pool, and the more people you add, the more “leave behinds” you get in a smaller volume of water so maintaining your tub will be different than a pool. 

Signs it’s time for a water change include the water getting hazy, having a harder time keeping the water chemistry balanced (you should be testing it regularly) and a bit of a funky smell. These are all signs it’s time to change the water! An approximate formula to calculate how often to change the water is to divide the total number of gallons of your hot tub by 3, then divide it again by the number of daily users. 

This formula is just a guess, not a rule; if you notice the water is cloudy and shocking it doesn’t seem to clear it, or you’re developing foam and defoamer isn’t having an effect, it is also likely time to change the water. Give us a call with questions at 970-879-4390 or contact us here.