The three main places to put chlorine tablets

Chlorine tablets go in one of three places: a floating dispenser, a skimmer basket, or a deck-mounted feeder. 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. Each method releases chlorine at a different rate, so the choice affects how often you need to check and refill.

The floating dispenser is the simplest and cheapest option if you do not have a feeder already. The skimmer basket is the most common choice for in-ground pools because it uses existing plumbing. A deck-mounted feeder gives you the most precise control but requires installation and is usually the most expensive upfront.

Key Takeaways

  • Floating dispensers work in any pool and cost under $20, but they drift around and release chlorine unevenly depending on water movement.
  • Skimmer baskets are built into most in-ground pools and release chlorine as water circulates, making them reliable and requiring no extra equipment.
  • Deck-mounted feeders attach to your pump system and let you control the exact rate chlorine dissolves, but they cost $200 to $500 and need installation.
  • Never drop loose tablets directly into the pool — they dissolve unevenly, can damage the pool floor, and create dead zones of high chlorine concentration.
  • Check your tablet dispenser every few days and refill when tablets are mostly gone, not when they disappear completely.

Using a floating dispenser

A floating dispenser is a plastic cage that holds one or two tablets and floats on the surface of your pool. Water enters through holes in the cage, dissolves the tablet slowly, and the chlorine disperses as the dispenser drifts. You can buy one at any pool supply store or online for $15 to $30.

The main advantage is simplicity — you just drop it in and it works. The main disadvantage is that chlorine release depends on water movement and sunlight. On calm days or in still corners of the pool, the tablet dissolves slowly. In windy conditions or near the return jet, it dissolves faster. This means your chlorine levels can swing up and down more than with other methods.

Floating dispensers also tend to get stuck against the wall or in corners, which can bleach the pool surface over time. If you use one, move it around every few days so it does not sit in one spot. They work best for above-ground pools and small in-ground pools where you do not mind checking levels more often.

Placing tablets in the skimmer basket

The skimmer is the rectangular opening on the side of your pool where water gets pulled in before it goes to the pump and filter. Most in-ground pools have one or two skimmers. Inside each skimmer is a basket that catches leaves and debris. You can put chlorine tablets directly in this basket instead of using a separate dispenser.

This is the most common method for in-ground pools because the water flow is steady and predictable. As water gets pulled toward the pump, it passes through the tablet and dissolves the chlorine evenly. The release rate stays consistent day to day, which makes it easier to keep chlorine levels stable. You do not need to buy any extra equipment.

The downside is that you cannot see the tablets easily — you have to open the skimmer lid to check how many are left. Also, if your pump is off, no water flows through the skimmer, so the tablet does not dissolve. If you turn the pump off for hours at a time, chlorine release stops. Some people use a skimmer basket insert (a smaller cage that sits inside the basket) to make refilling easier, but it is not required.

Installing a deck-mounted chlorine feeder

A deck-mounted feeder is a plastic box that attaches to the deck or equipment pad near your pump. Tablets go inside, and a valve controls how fast water flows through them. The feeder connects to your pump system with PVC pipe, so chlorine-treated water goes directly into the circulation line.

This method gives you the most control. You can adjust a dial or valve to speed up or slow down how fast the tablet dissolves, which lets you dial in your chlorine level precisely. The release rate does not depend on where the feeder sits or how much wind there is. If you have a pool that needs very stable chlorine levels or you want to minimize testing, this is the most reliable option.

The trade-off is cost and installation. A basic deck feeder runs $200 to $500, and you may need a pool technician to install it if you are not comfortable working with PVC and pump connections. Some feeders also require a small amount of electricity to run a solenoid valve. Once installed, though, they are very low-maintenance — you just refill tablets every week or two and adjust the dial as needed.

What not to do with chlorine tablets

Never drop loose tablets directly into the pool. Tablets are compressed chlorine and they dissolve slowly. If you throw one in, it sinks to the bottom and creates a spot of extremely high chlorine concentration around it. This can bleach or damage the pool surface, especially vinyl liners. It also creates uneven chlorine distribution — the area around the tablet has way too much chlorine while the rest of the pool has too little.

Do not put tablets in the deep end and expect them to dissolve evenly. Water does not circulate well in deep spots, so the tablet sits there and dissolves very slowly. The chlorine that does dissolve tends to stay in that area instead of spreading throughout the pool.

Do not leave a floating dispenser in direct sunlight for days without checking it. Sunlight can degrade the plastic and cause the dispenser to crack or leak. Also, do not assume that because you put tablets in on Monday they will last until Friday. Check every two to three days and refill when the tablets are mostly gone, not when they disappear completely. Running out of chlorine for even a day or two can let algae start to grow.

How to refill your dispenser or skimmer

For a floating dispenser, turn it upside down to open the bottom cap. Remove any leftover tablet pieces and rinse the cage with pool water. Drop in one or two new tablets depending on the size of your pool and how fast you want chlorine to release. Close the cap and put it back in the water.

For a skimmer basket, turn off the pump first. Open the skimmer lid and lift out the basket. If you are putting tablets directly in the basket, remove any tablet pieces and drop in new ones. If you are using a basket insert, remove the insert, empty it, rinse it, and add new tablets. Put the insert back in the basket, replace the basket, and close the lid. Turn the pump back on.

For a deck-mounted feeder, open the top cover and remove the old tablet pieces. Rinse the chamber with a hose if there is a lot of residue. Drop in new tablets — most feeders hold two to four tablets at a time. Close the cover and check the valve setting. If your chlorine level has been running high, turn the dial down slightly. If it has been running low, turn it up.

Checking chlorine levels after you add tablets

After you refill your dispenser or skimmer, test your chlorine level the next day. Use a test kit or test strips — they cost $10 to $30 and are available at any pool supply store. The ideal chlorine level is 1 to 3 parts per million (ppm) for a residential pool. If your level is too high after a day, your tablets are dissolving too fast. If it is too low, they are dissolving too slowly.

With a floating dispenser, you can move it to a different location to change the release rate — move it toward the return jet to speed up dissolution, or to a calm corner to slow it down. With a skimmer, you can add or remove tablets to adjust the level. With a deck feeder, turn the valve dial to adjust the flow rate.

It usually takes two to three days for chlorine levels to stabilize after you change something. Do not adjust again until you have tested at least twice and seen the same reading both times.

Frequently Asked Questions

Can I use chlorine tablets in an above-ground pool?

Yes. Floating dispensers work best for above-ground pools because they are straightforward and do not require installation. You can also use a skimmer basket if your above-ground pool has a built-in skimmer, though many do not. Deck-mounted feeders are rarely used on above-ground pools because the cost is not worth it for a temporary or seasonal pool.

How often do I need to refill chlorine tablets?

It depends on your pool size, how much sun it gets, and how much it is used. Most pools need a refill every five to seven days. Check your dispenser every two to three days so you catch it before it runs completely empty. If your pool is very large or gets heavy use, you might refill every three to four days.

What happens if I run out of chlorine tablets?

Chlorine levels drop quickly without a source. Within one to two days, the level can fall below 0.5 ppm, which is too low to prevent algae growth. If you run out for more than a day or two, you may see green water or cloudy water. You can fix this by adding new tablets and testing daily until the level comes back to normal, usually within two to three days.

Can I use different brands of chlorine tablets together?

Yes. All chlorine tablets are similar — they are compressed calcium hypochlorite or trichlor. Mixing brands does not cause any chemical reaction or problem. The only thing that matters is the total amount of chlorine you are adding, not which brand it comes from.

Do I need to turn off my pump to add tablets to the skimmer?

It is safer to turn off the pump first. If the pump is running and you open the skimmer lid, water can splash out or the suction can be strong enough to be uncomfortable. Turning it off takes 30 seconds and prevents accidents. You can turn it back on when ready after you close the lid.