Chlorine is a chemical added to swimming pools to keep the water free of bacteria and algae. Chlorine levels in swimming pools vary, based on how much chlorine has already been used to remove bacteria and how much sunlight has broken down the chlorine molecules. This means pool owners spend a lot of time testing and adjusting the levels of chlorine in their pools. To reduce the amount of time spent on pool maintenance, pool chemical manufacturers created chlorine tablets, made by pressing together chlorine and a stabilizing agent that acts as a sunscreen for the chlorine. This combination allows pool owners to add chlorine tablets that will slowly release chlorine in the pool water over time, minimizing the amount of water testing and pool maintenance required to keep the pool clean.

Jacuzzi spa pool qualiter water tester and tablet of chlorine or bromide
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Chlorine tablets let you keep pool water clean with fewer water tests and adjustments.

Tablet Chlorinators

Chlorine tablets are best used with tablet chlorinators. A chlorinator is a device installed as part of your pool's filtration system. When properly installed, the chlorinator is the last thing your pool water passes through before returning to the pool. Periodically, you will need to fill the chlorinator with chlorine tablets. You then set the dial on the chlorinator to between 1 and 3 ppm. The chlorinator regulates the amount of chlorine in your pool, adding chlorine from the tablets as needed. You simply need to keep the chlorinator stocked with tablets, and it does the rest.

Skimmer Basket Chlorination

Rather than invest in a chlorinator, some pool owners simply drop chlorine tablets into their pool skimmer. One 3-inch chlorine tablet will chlorinate 5,000 gallons of pool water. You can calculate how many tablets you need for the size of your pool, place the tablets in the skimmer and let your pool filter distribute the chlorine along with the water returning to the pool.

Use caution, however, when using this chlorination method. While the skimmer method works fine when the pump is running, you're headed for trouble if you leave chlorine tablets in your skimmer while the pool pump is off. The chlorine tablets are made to dissolve and will continue to do so whether your pool pump is running or not. Chlorine is corrosive, so any tablets left sitting in your skimmer when the pump is off could corrode pipes and other equipment. As the water sloshes in your pool, overly chlorinated acidic water could also splash back out of the pool skimmer and ruin your pool liner. If you need to turn your filter off for any reason, remove any chlorine tablets in your skimmer basket first.

A Word on Floating Chlorinators

Pool Chlorine
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Floating chlorinators like this one can get stuck in your pool and cause damage.

Some pool supply companies sell floating chlorinators, but these are not recommended. As their name suggests, floating chlorinators float on the top of your pool water. The theory is that you add chlorine tablets and let the floater move freely around your pool, slowly releasing chlorine as the pool water interacts with the tablets through holes in the bottom of the floater. Chlorine, however, is highly acidic and corrosive. It is common for floaters to get stuck or hung up on pool ladders or walls. When this happens, the chlorine stays in one place, where it can damage the liner and corrode pool materials. Floaters are best avoided for the sake of your pool's longevity.