Chlorine tablets all information and FAQs.

Swimming pool chlorine tablets - what exactly do they do?

Chlorine tablets per 3

Chlorine tablets are slowly dissolving chlorine

Chlorine tablets are slowly dissolving chlorine tablets or cylinders that disinfect the water by dissolving it in the swimming pool water.

The 4 most commonly used chlorine tablets are:

    • The current chlorine tablets of 200g
    • HTH chlorine sticks - cylinders of 300g
    • MTF 5 in 1 tablets with all in 1
    • 20g Chlorine tablets for jacuzzis and above-ground swimming pools

How do I use the chlorine tablets?

Chlorine tablet skimmer

Dose chlorine via the skimmer basket

Chlorine tablets or HTH Chlorine sticks resolve slowly and place you in the skimmer basket from the pool. This allows you to gradually dose chlorine every time your circulation pump works and the pool water passes through the skimmer to the filter. For example, chlorine tablets or HTH tabs dissolve slowly. Consequently, the pool water will be disinfected in this way.

Hayward Rainbow chlorine dispenser

Chlorination via a chlorine dispenser.

A 2nd possibility to add chlorine liquid to the swimming pool water is via a chlorine dispenser or chlorine feeder. This is a device that you put in By-Pass over the filter installation of the swimming pool. You add the tablets in this tube. The swimming pool water partly flows through it, so you can dose a strong chlorine water in the swimming pool with chlorine tablets.

Chlorine tablet in floating skimmer

Chlorine pills in a floating skimmer

With smaller design pools you can use the smaller one Place 20g chlorine tablets in a floating skimmer. This is the simplest way. On the other hand, it is slightly less efficient, because the pool water does not flow well past the tablet. The tablet with chlorine will therefore dissolve a little more slowly.

Frequently asked questions about chlorine tablets.

The short answer is NO. This type of chlorine should not be used in public swimming pools from eg hotels, wellness centers or other public baths. Our tablet is approved for use in Belgium and the Netherlands in private swimming pool water disinfection but not for public swimming pools. For public swimming pools you can DO NOT use the stabilized chlorine from HTH.

In summary :

If the chlorine you measure in the pool is too high, higher than 2ppm, it is recommended to use the pool dilute with fresh water or adding a product – sodium thiosulfate around the to neutralize chlorine.

  • a backwash of the sand filter
  • by waiting for the chlorine in the pool to break down (by sun or rain). This method is only feasible with a small excess of chlorine.
  • if you have used too many 200g chlorine tablets, there is a 3rd possibility, namely dosing a product to lower the chlorine. This product is sodium thiosulfate.

It is best to postpone swimming until the chlorine value has dropped below 3 to 2 ppm. A chlorine value below 3 ppm is safe again.

USEFUL : POISON CENTER : 070/245.245

Shelf life chlorine tablets 200g

The shelf life of a bucket of Chlorine tablets 200g – SLOW is 4 years old. The chlorine in tablets of 200g are packed in a 5kg bucket. Each product is individually packaged in a plastic bag. If you use the bucket store dry and cool shelf life is very long. You can certainly keep these tablets for 2 seasons. Chlorine tablets 200g will not degrade or pulverize. The proper functioning and disinfectant power of the product persists for several months to years. Our chlorine tablets are approved for use in swimming pools.

Usually the shelf life from date of manufacture will be 4 years. The high quality of the chlorine is guaranteed by good control. That is why every production batch has a batch number. This makes the products + the production itself traceable. If a quality problem should arise, our chlorine tablets can be traced perfectly.

We advise to 1 tablet of 200g for 30m³ or 1 HTH Stick 300g for 40m³ to be placed in the skimmer per week and 1 – 2ppm chlorine to add to the water. The dosage depends on a number of points:

    • the flow rate of the circulation pump – if your filter pump eg 12h works you will add more chlorine than eg when the pump only circulates 8h
    • if the water is very warm, the tablets with chlorine will also dissolve faster and therefore dose more
    • for example, if you do not cover the swimming pool, the chlorine will disappear faster due to degradation by the sun and evaporation, so you will have to add more chlorine tablets
    • if there is a lot of swimming, you will also have to add more chlorine product
    • For example, HTH chlorine tablets dissolve more slowly than “regular” 200 g chlorine tablets

To follow an accurate dosage you must measure the chlorine. When you measure the chlorine and it is lower than 1 to 2 ppm, it is best to add a tablet or let the pump circulate more. If there is no chlorine to be found at all, it is best to do a chlorine shock in the swimming pool chlorine granulate to get the chlorine back on track quickly.

There are different types of chlorine in tablet form. Here's an overview

  • Chlorine tablets 200g or chlorine tablets SPA 20g consist of Trichloroisocyanuric acid 90% – Organic chlorine
  • HTH Sticks 300g are made of Calcium hypochlorite 69% – inorganic chlorine
  • MTF 5 in 1 chlorine tabs are made from oa as well Trichloroisicyanuric acid 90% but also contain other raw materials
  • HTH Chlorine Pastilles 7g are also made from Calcium hypochlorite 69%

Tablets of stabilized chlorine are typically used in private swimming pools. HTH chlorine or NOT stabilized chlorine tablets may also be used in public swimming pools.

Chlorine tablets (200g) are a dangerous chemical product. It is best to ensure that your skin does not come into contact with the product. It is therefore best to wear gloves to place the chlorine disc in the skimmer basket or in the chlorinator. The 200g chlorine tablets are packed in a plastic bag to avoid contact. The HTH chlorine tablets are cylinders of 300g and have a plastic casing

  • At the 200g chlorine disc must it be plastic bag OFF
  • At the 300g chlorine cylinder from HTH must it be plastic casing STAY TO IT

Safety regulations

May irritate eyes and respiratory tract. Is very toxic to living organisms. Never mix this chlorine product with acid. Chlorine in combination with acid forms a poisonous gas.

POISON CENTER: 070245245

Chlorine alone will not kill the mosquito larvae. Several points of attention are needed to prevent the growth of mosquito larvae.

    • Take care first of all very good circulation. Filter 6 – 8h per day
    • Make it one “skimmer” is present in the pool as much as possible upper water layer will suck in and filter
    • brush regularly the walls and the waterline from the pool
    • Love the concentration of chlorine at 1.5 – 2ppm. Chlorine will not kill the mosquitoes but will make the conditions for the growth of the larvae more difficult.
    • The rinse the sand filter regularly for a clean filter and good filtration
    • Use a net for it to delete by surface dirt
    • Seal the pool surface during the night or when you are not using the pool.

With a chlorine disc you can green swimming pool water ready again but not bright. Chlorine will kill algae or other bacteria. As a result, the green swimming pool will clear up and the green color goes away. But the pool water will remain very cloudy and milky. Here are some tips to get the pool water crystal clear again:

    • correct the pH value to pH 7.2
    • let the filter pump run 24/24h and circulate the water
    • place one flake agent in the skimmer basket
    • rinse the sand filter every day and add fresh water
    • clean the pool with a pool robot

If the pool water contains sufficient chlorine but is not clear or cloudy, the first reflex should be to check the pH value of the pool water. This must be adjusted absolutely correctly at 7.2 – 7.3. If you add fresh water, the pH value will change. After the acidity of the pool water is correct, add a chlorine shock with chlorine granulate. It HTH chlorine granulate is the swimming pool chlorine with the highest concentration of active chlorine. If this acidity is OK, you can use flocculant. With e.g Flovil Super Flocculation you will make the pool water crystal clear again in a very short time.

READING TIP : Make green swimming pool water clear

For various reasons, you should NOT use pool chlorine in toilets. First, this is for the sake of the much too high concentration of the chlorine. Therefore, these very highly concentrated chlorine tabs damage the pipes, the drain and the toilet itself.

Second, do you have a septic tank? Then this chlorine will also kill all the benign bacteria in the septic tank and thus destroy the biology of the system.

The third risk is the gas formation. For example, if you were to use an acid-based descaling product, this acid and the chlorine could create dangerous chemical fumes.

In summary so it is absolute NOT A GOOD IDEA about chlorine pills or chlorine tablets at to go use in a toilet.

Chlorine tablets are no worse or better than liquid chlorine. There are 3 main differences.

  1. Composition : chlorine tablets consist of trichloroisocyanurate – liquid chlorine consists of sodium hypochlorite
  2. The application : chlorine tablets are for manual dosing - liquid chlorine for automatic dosing
  3. The third difference is the reaction speed : chlorine tablets are slow dissolving – whereas liquid chlorine is fast dissolving

Are you wondering whether it is better to use the regular or the sticks for your swimming pool? Well, if you regularly backwashed, so also prevents the concentration of stabilizer from becoming too high, then you can use the regular tablets of 200g to use. So this is usually one outdoor pool.

Do you backwash less, e.g in an indoor pool then you better the Using HTH Sticks. Due to evaporation, the concentration of the stabilizer (Cyanuric acid) will quickly become too high and you will have to dilute when using the regular tablets. (read all about overstabilization here)

TIP : Find out everything about HTH Sticks – chlorine tablets for your swimming pool here.

Then, of course, there's the VLAREM II regulations. Is your pool a public or semi-public swimming pool – eg a hotel or wellness centre, then you must use 'biocide class A'. These are the NOT stabilized chlorine tablets like the HTH sticks. (or e.g liquid chlorine)

Which chlorine tablets should I use?

Chlorine tablets

You can use all types of tablets with chlorine. So both the Chlorine discs 200g, the HTH Chlorine Sticks 300g and the MTF 5 in 1 chlorine tablets.

You can place this in the skimmer of the swimming pool. In this way, the tablets dissolve and ensure an even disinfection of the pool water.

HTH chlorine pastilles 7G - Use a chlorine floater for this - Occasionally when dosing with HTH Chlorine Granules

Chlorine tablets contain Trichloroisocyanic acid. What exactly is trichlor?

Add manually on a regular basis HTH Chlorine Granulate and measure with the measuring strips until you have enough chlorine. HTH Pastilles or AQT chlorine tablets SPA 20g are suitable for permanent dosing.

Then just use Liquid chlorine With automatic dosing, the dosing pump will suck up the product and dose it into the pipe to the pool. You therefore need a liquid chlorine product for this. That is why this chlorine is the most suitable product for this liquid chlorine.

Just use the tablets of 200g. These pills fit perfectly in the tube of the chlorine dispenser. The Nature 2 cartridges have been banned since 2015 and can therefore no longer be purchased. This tube in your Zodiac Nature 2 system can be left empty.

Here is an overview of all types of chlorine

1. The HTH Chlorine Sticks

HTH chlorine sticks are cylindrical chlorine cartridges that do not contain a stabilizer and are made of calcium hypochlorite. The advantage of this type of pool chlorine is that it does not "over-stabilise" your pool and therefore never blocks the disinfection function

2. Chlorine tablets MTF 5 in 1

In addition to chlorine, 5 in 1 tablets also contain; stabilizer - flocculant - pH regulator and anti-algae. That is why the MTF chlorine is extremely easy to use and ensures much more balanced swimming pool water.

3. Liquid Chlorine

We use liquid chlorine for automatic dosing systems at swimming pools. This is easier to use but is less concentrated and will degrade over time.

4. HTH Chlorine Pastilles

Small chlorine pastilles are small chlorine tablets of 7g or 20g that are mainly used in jacuzzis.

5. Chlorine granulate

We use chlorine granules to give a shock to the swimming pool water and to temporarily have an excess of chlorine. This then causes a shock disinfection.

6. Chlorine Tablets 20g

For smaller pools and above-ground pools, you can use small ones chlorine tablets SPA 20g to use. You can also use these small chlorine tablets in a jacuzzi.

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