The Three Main Placement Options

Chlorine tablets go in one of three places: a floating dispenser that drifts on the water surface, a skimmer basket built into your pool's circulation system, or a chlorine feeder (also called a chlorinator) that attaches to your pool's return line. Which one you use depends on your pool setup, how much control you want over chlorine levels, and whether you have the equipment already installed.

The floating dispenser is the simplest and cheapest option if you're starting from scratch. The skimmer basket is convenient if your pool already has one and you want a hands-off approach. The chlorine feeder gives you the most precise control but requires either existing plumbing or professional installation.

Key Takeaways

  • Floating dispensers hold tablets on the water surface and work best for pools under 15,000 gallons, though they can damage vinyl liners if left in one spot too long.
  • Skimmer baskets dissolve tablets as water circulates through them, making them convenient if your pool already has a skimmer, but they can corrode metal parts if you use the wrong tablet type.
  • Chlorine feeders attach to your return line and deliver chlorine at a steady rate, giving you the most control but requiring installation or existing plumbing.
  • Never drop tablets directly into the pool water — they dissolve unevenly, can damage the pool surface, and create dangerous chemical pockets.
  • Check your tablet type before placement: stabilized tablets (trichlor) work in skimmers and feeders but can over-stabilize; unstabilized tablets (calcium hypochlorite) should only go in floating dispensers.

Using a Floating Dispenser

A floating dispenser is a plastic cage or tube that holds one to three tablets and floats freely on your pool surface. You fill it with tablets, close the lid, and let it drift around. As water circulates and splashes through the cage, the tablets dissolve slowly. This method works well for pools up to about 15,000 gallons and requires no installation.

To use one, unscrew or unclip the top, drop in your tablets (usually one to three depending on pool size and water temperature), and seal it shut. Place it in the deepest part of your pool away from the skimmer intake — if it gets sucked into the skimmer, it can jam the basket. Check it every few days and refill when tablets are mostly gone. The dispenser will move around on its own, but if you notice it staying in one corner, move it manually to prevent bleaching or damage to vinyl liners.

The main drawback is that you have less control over chlorine levels because the dissolution rate depends on water temperature and circulation. In cold water, tablets dissolve slowly; in hot water, they dissolve faster. Also, if your pool has a vinyl liner, leaving the dispenser in one spot for days can bleach or weaken the material.

Using Your Pool's Skimmer Basket

If your pool has a skimmer — the intake box on the pool wall that pulls in surface water — you can place tablets directly in the skimmer basket. As water flows through the basket toward your filter, it dissolves the tablets. This is convenient because you don't need extra equipment, and the tablets dissolve at a steady rate tied to your pump's circulation.

Open the skimmer lid, remove the basket, and place one to two tablets inside (depending on your pool size and the tablet type). Replace the basket and close the lid. Check it every few days and add new tablets when the old ones are mostly dissolved. Most people refill once or twice a week during swimming season.

The catch is that chlorine tablets are acidic and can corrode metal parts in older skimmers or return lines. If your skimmer has aluminum or uncoated steel components, the acid will eat away at them over time. Also, if you use trichlor tablets (the most common stabilized type), the stabilizer builds up in your water over the season and can make your pool harder to balance. Some pool owners switch to calcium hypochlorite tablets in skimmers to avoid this, but calcium hypochlorite is less stable and works better in floating dispensers.

Installing a Chlorine Feeder

A chlorine feeder (or chlorinator) is a device that attaches to your pool's return line — the pipe that sends filtered water back into the pool. Tablets go inside the feeder, and as water flows through, it dissolves them at a controlled rate. This gives you the most precise chlorine levels because the dissolution rate is tied directly to your pump's flow rate.

Installation requires either existing plumbing connections or cutting into your return line and adding the feeder with PVC fittings. If you're not comfortable with plumbing, hire a pool professional. Once installed, you straightforward drop tablets into the feeder's chamber, close the lid, and let it run. Most feeders have a dial or valve you can adjust to speed up or slow down the dissolution rate.

The advantage is steady, predictable chlorine levels and no risk of damage to your pool surface or liner. The disadvantage is upfront cost and installation time. Feeders also require you to turn off your pump before opening the chamber to add tablets, which takes a few minutes each time.

Tablet Types and Where They Go

Not all chlorine tablets are the same, and placement matters. Trichlor tablets (three-inch white tablets) are stabilized with cyanuric acid and dissolve slowly. They work well in skimmers and feeders but should not go in floating dispensers because they can damage vinyl liners. Calcium hypochlorite tablets (smaller, white or tan) are unstabilized and dissolve faster. They work best in floating dispensers and should not go in skimmers because they can corrode metal parts.

Check your tablet packaging to see which type you have. If you're unsure, ask your pool supply store. Using the wrong tablet in the wrong place can corrode equipment, damage your liner, or create uneven chlorine levels.

Common Mistakes to Avoid

Never drop tablets directly into the pool. They will sink, dissolve unevenly, and create pockets of high chlorine concentration that can bleach the pool floor or damage the surface. They can also be a safety hazard if someone swims over them.

Do not leave a floating dispenser in the same spot for more than a day or two. It will bleach vinyl liners and can weaken the material. Move it around or remove it when you're not actively using it.

Do not mix tablet types or brands in the same dispenser or feeder. Different formulations dissolve at different rates and can react unpredictably. Empty the device completely before switching types.

Do not overfill your dispenser or feeder. Too many tablets dissolve too fast and can spike your chlorine to unsafe levels. Start with the number recommended for your pool size and adjust based on test results.

Testing and Adjusting Chlorine Levels

Placement alone does not may provide the right chlorine level. You need to test your water regularly — ideally two to three times a week during swimming season. Use a test kit or test strips to measure free chlorine. The target is 1 to 3 parts per million (ppm) for a residential pool.

If your chlorine is too low, add tablets or move your dispenser to a spot with more water circulation. If it's too high, remove tablets and let the sun break down the excess (this takes a day or two). In winter or when the pool is not in use, you can remove the dispenser or feeder entirely and store it indoors.

Frequently Asked Questions

Can I use a floating dispenser in a pool with a vinyl liner?

Yes, but move it around daily or remove it when you're not swimming. Leaving it in one spot bleaches and weakens vinyl. If you have a vinyl pool, a skimmer basket or feeder is often a better choice because the tablets stay in one place and don't contact the liner.

What happens if I put the wrong tablet type in my skimmer?

Calcium hypochlorite in a skimmer can corrode metal parts and cause the basket or return line to rust or pit. Trichlor in a floating dispenser can damage vinyl liners. Always check the tablet type and match it to the placement method recommended on the package.

How often should I refill my dispenser or feeder?

Check every three to five days during warm weather and refill when tablets are mostly dissolved. In cooler weather, tablets last longer. The exact timing depends on your pool size, water temperature, and how much the pool is used. Weekly checks are a safe habit.

Can I use a chlorine feeder if my pool does not have one installed?

Yes, but you will need to install it or hire a professional to do so. It requires cutting into your return line and adding PVC fittings. If installation is not practical, a floating dispenser or skimmer basket are simpler alternatives that require no plumbing work.

Is it safe to swim while tablets are dissolving?

Yes, as long as the tablets are in a dispenser, skimmer, or feeder — not loose in the pool. The chlorine dissolves gradually and mixes with the water. If you add tablets and test your chlorine level within an hour, it will likely be safe to swim. Always test before allowing children or guests in the water.