New Uses for Old Hot Tub Water
Reduce, Reuse and Recycle your hot tub water. Hot tub and spa owners generally replace their spa water every 90-120 days, or every 3-4 months. The reason for this is that the water becomes choked with invisible (at first) solids, minerals and contaminants that overwhelms the spa filter and sanitizer. This leads to cloudy, dull spa water which may be unhealthy.
Draining and refilling a spa or hot tub is a relatively simple and painless process, but what if your region is undergoing water restrictions, or for your own environmental reasons, you want to drain the spa fewer times per year?
In some cities and counties, draining your spa can be a punishable offense, with fees or fines that create an incentive to extend the time between spa water changes.
Here's 6 ways to recycle old hot tub water or re-purpose spa water to other uses, and 8 ways to extend your hot tub water lifespan, so you don't need to drain so often.
6 Ways to Reuse Hot Tub Water
Water your lawn
Spa water makes fine lawn water, as long as you open the cover and allow the chlorine or bromine level to drop to around 1 ppm. It need not be at zero, but it shouldn't be higher than 3 ppm, or certain types of grasses may object and start to turn a yellow color after a few days. Your spa water should also be relatively well balanced, or at least the pH level should be below 7.8, and even 7.0 to 7.2 if possible, as most lawn grasses prefer a slightly acidic pH level. Move the hose around every half hour, so you don't over-saturate one area of the lawn.
Water your trees and bushes
Spa water also makes fine water for trees and bushes, again as long as the chlorine or bromine level is not off the chart, it's ok to have 1-2 ppm, which is the same amount you might find in a tap water test. Plants that have been accustomed to chlorinated water (from municipal water supply), can tolerate even higher levels, but it's always best to open the spa cover, and run the jets for awhile, to allow chlorine to dissipate to a safer level, below 3 ppm. If your spa uses a saltwater spa system, be sure that your plants and trees are salt-tolerant before using spa water for irrigation.
Water your home foundation
For those that live in the drier parts of the country, you may have heard horror stories of home foundations cracking when the ground becomes too dry. Or new concrete driveways or walkways that can settle if the ground beneath dries and shrinks too much. In times of drought, when rainfall is scarce, hot tub water can be used to soak the ground around the home, or near concrete placement. This soaks into the soil, expanding it to a greater volume, for support of heavy concrete and steel structures.
Pump it into your pool
Sure why not? Unless it's dark green and super funky, a large swimming pool can easily absorb a few hundred gallons of spa water without batting an eyelash. It's actually what I do, when I'm not needing to water the lawn or my plants, I just run the hose over to the pool and recycle my spa water, magically turning it into pool water.
Pump it into a doggy pool
During the hotter parts of the summer, my dogs love to take a dip, but they know not to go in the pool, with my direct (adult) supervision. I bought a Walmart kiddie pool a few years ago for my dogs. Now when I do a spa water change in the summer, I use about 80 gallons of hot tub water to fill up the doggy pool (kiddie pool), repurposing my old spa water, and (magically) turning it into doggy pool water.
Wash your car or boat
For this trick you will need a submersible pump, and a long garden hose to reach the driveway. I have used my spa water to wash our 2 cars, with some left over to water the front lawn. Since a submersible pump should not be used with a spray nozzle, the hose is constantly running. Place the hose on the lawn during the times you are scrubbing the car (or boat), you can kill two birds with one stone. If you have a community water watch organization on patrol, you may need to explain that you are recycling your hot tub water, and not just letting tap water run down the driveway.
8 Ways to Extend Hot Tub Water Life
Maintain optimum water balance
Keeping your spa pH, Alkalinity and Calcium Hardness levels not only makes the water more enjoyable to soak in, but allows your sanitizer and filter to work more effectively, keeping your water from spoilage sooner.
Shower before using your spa
Reducing the amount of oily, flaky, gunky stuff into the spa could be the number one thing to extend your spa water lifespan. For those that treat their hot tub like a bath tub, this creates a huge demand on your spa filter and sanitizer, and leads to smelly, cloudy and possibly unsafe water conditions. You don't have to take a shower every single time, but if you need a shower, be sure to wash up well with soap and water before using the spa. And keep your head and hair out of the water, to reduce oil and soap contamination.
Shock after using your spa
Even though you are careful to wash before using the spa, shocking the spa after use is a good way to extend hot tub water life. But depending on how many people are using the spa, and for how long, a spa shock treatment may not be always needed. Use your judgement, but try to shock the spa at least once per week, to break apart chemical compounds and contaminants and kill any algae or bacteria.
Install a larger or second spa filter
We've covered this idea before, you can sometimes find the same size spa filter cartridge in a larger square footage size. This means that you increase the filter surface area, with a cartridge that has more pleats per inch. More surface area means better filtration. Another way to improve filtration is to use a Microban cartridge, which is coated with a bacteria killing layer (these are the Blue spa filters). Thirdly, you can install a second spa filter, inline underneath the spa, or an external filter placed beside the spa. With enough square footage of filter area, you could easily double or triple your spa water life.
Install an ozonator or mineral purifier
Anything that helps kill bacteria or remove contaminants from the spa water will increase water quality and lengthen the time between draining a hot tub. Ozonators and Mineral Sanitizers are two ways to do this, without heavy reliance on bromine and chlorine. You can reduce the need for halogen sanitizers like bromine and chlorine, while at the same time improving water quality and increasing the time between water changes.
Use spa clarifier or spa enzymes
Spa clarifiers are used to improve your spa filtration. They work to increase the particle size by coagulating suspended particles together, in a size that won't pass right through the filter. Used regularly, spa clarifiers can stave off an impending water change by allowing the filter to keep the water cleaner, reducing cloudy and dull water. The same is true for spa enzymes, many of which are mixed with clarifiers. Enzymes are organic creatures that consume oils and gunk in the water, actually removing them and reducing the work for your filter and sanitizer.
Use a spa water prefilter when filling
Especially for those on a well, or for city water supply that is not always clean or perfectly balanced, using a spa pre-filter when you fill the spa can lead to a longer water life. A hot tub pre-filter screws on the end of your garden hose and filters out minerals, metals, chloramines, contaminants, oils - leaving you with very pure water - H2O. When you start with clean fresh water, with a low TDS (total dissolved solids) level, you can add weeks or months to the life of your spa water. I always use a pre-filter, and can tell you that it does make a difference!
Filter the water longer each day
Many spa owners naturally try to reduce their energy use with the spa, but reducing your filtering time too much can cost you more money in chemicals and water changes. For those spas with a 24 hr circulation pump - run the pump 24 hours, but also be sure to have a few jet pump runs during the day, to force high pressure water through the pipes and filter. This helps avoid biofilm cultures from growing and prevents dead zones in the spa circulation. If your spa water turns cloudy or dull too easily, you may need more daily filtration, and/or a new spa filter cartridge.
Look to find ways to reuse your spa water around the home, and try to improve your water quality so you only need to drain your spa 2 or 3 times per year, instead of 3 or 4...