Hot Tubs, Swim Spas, Service, and Maintenance

Water Chemistry: Basics


WATER CHEMISTRY can be very frustrating for new pool and spa owners along with old pros because sparkling, beautiful and inviting water can turn quickly to look dull, nasty and un-swimmable water seemingly overnight.  Before you give up and fill your pool with dirt and make a garden spend a few minutes going over basic water chemistry and see what you might be forgetting.  Some simple steps can lead to clean clear water.

Water needs to be sanitized (chlorine, bromine) to kill bacteria and viruses that can cause diseases, pathogens and make the water look generally uninviting.  High or low pH levels can affect how your sanitizer works and can also affect other parts of your pool or spa.  Poorly treated water can void manufacturer warranties because it can ruin the mechanical parts of your swimming pool or hot tub, so taking care of your water is essential.  Luckily, it is not that hard, you just need to remember to take care of it and not forget. Below is the minimum amount of care every pool and hot tub needs.

  1. Circulation and Filtration- Circulation and filtration make sure that the water does not get stagnant by continuously circulating the water.  This adds oxygen to the water and makes it healthier.  Filtration goes with circulation, and if your filters are clogged or dirty your pool or hot tub won't get clean.  Cloudy water can be attributed to a number of sources, but one big cause of cloudy water is poor filtration or dirty filters, so before you do anything else figure out when the last time you cleaned and changed your filters.  This will save you time and money.  If you have cartridge filters it is a good idea to have the measurements of the cartridge before you try to order a replacement.
  2. Cleaning- Keep the sides of the pool and hot tub clean, especially the areas that don't seem to get much circulation; most pools have dead areas, where the water doesn't seem to move much.  This is where algae tends to start growing first, because of the lack of circulation.  You should manually brush these walls down weekly so that algae and other microorganisms don't have a chance to attach and grow.  Vacuum your pool weekly as well. An auto-vac is a nice addition to your swimming pool.
  3. pH and Alkalinity- All pools and spas need their pH and alkalinity checked because they affect how the sanitizer is working. The higher pH is, the more it affects your chlorine's ability to sanitize properly, so proper pH levels are very important to keeping your pool clean. In addition, alkalinity affects how your pH can be raised or lowered, so knowing what your alkalinity is, helps make sense of why your pH is doing what it is doing. Low pH and/or alkalinity can cause corrosion and costly damage. This will also void warranties. Do not ever let your pH get below 7.0. Checking and adjusting frequently will save time and money in the long run.
  4. Sanitation- Chlorine or another type of sanitizer keeps the bacteria and viruses from growing in your pool water.  Proper sanitation is very important.  Knowing how your chosen sanitizer reacts to your climate is also very important because you can anticipate how you will need to react during your swimming season.  Our desert summer is very intense and it is very hard to keep chlorine levels in your pool sometimes, but if you are aware of this, it is much easier to be proactive instead of being constantly playing catch-up with your chlorine all season and wondering why your pool is always cloudy and dirty.  Stay on top of the chlorine in the summer and back way off in the cooler months when you won't go through as much.  Checking chlorine daily or every other day with a test strip will help to stay on top of it. That way you catch it before it gets too low or too high. Too low causes bacteria to take hold, which then causes cloudy and sometimes green water. Too high of chlorine can damage the equipment and some types of pools.  For a hot tub, bromine is a much more popular choice, and there are also many more options such as the Frog@Ease system.
  5. Oxidize- Shock the pool or hot tub regularly to get rid of dead waste.  This will make the water look and smell much nicer.

The Centers for Disease Control recommend that chlorine levels for swimming pools be kept between 1.0-3.0 ppm (parts per million) to effectively sanitize the pool without causing swimmer irritation. PH levels should be kept between 7.2-7.8, anything above or below causes irritation to swimmers and equipment.  Low pH corrodes and also causes skin and eye irritation, while high pH causes scale to deposit as well as skin and eye irritation.