Chlorine Chemistry

Chlorine (Cl) in its molecular form is a gas and is not commonly used in residential pool applications as it is a very dangerous form to use chlorine in.

There are four commonly used forms of chlorine in residential swimming pool applications as follows:

  1. Sodium Hypochlorite – Liquid Chlorine – Click for more
    Liquid Chlorine is relatively cheap and easy to use. It can be directly poured in to any pool and immediately releases free chlorine in to the water. It has a significant upwards effect on ph and a ph down product (such as muriatic acid) will need to be used in unison. Liquid chlorine can be used to very quickly raise the chlorine level.
  2. Calcium Hypochlorite – Granular chlorine (Unstabilized) – Click for more
    Granular Chlorine is also relatively cheap and also contains calcium. It need to be carefully added to most pools as it is a heavy compound and very quickly settles and sinks to the bottom which can cause pool surfaces to stain and wear. It is a good idea to dissolve granular chlorine in a bucket before adding it to the pool. Similarly to liquid chlorine, granular chlorine can be used to very quickly raise the chlorine level and will also cause the ph to drift upwards.
  3. Dichloroisocyanuric Acid – DiChlor – Click for more
    DiChlor is most commonly used in dissolvable tablets. It has an almost neutral effect on ph and so is great to use in situations where ph is significantly drifting. DiChlor is also stabilised which means that it will add sunblock to the water and prevent chlorine loss (however Sunblock levels do need to be carefully monitored). Tablets will not quickly raise the chlorine level but rather slowly dissolve and maintain a chlorine level with additional shock doses of granular or liquid chlorine added to the pool when needed.
  4. Trichloroisocyanuric Acid – TriChlor – Click for more
    TriChlor is also most commonly used in tablet form. It is unique in that unlike all the above chlorine types it will actually lower the ph. TriChlor also contains Sunblock, which will prevent chlorine loss, but again needs to be carefully monitored. TriChlor has a higher available chlorine content then all other types. As with all tablet forms of chlorine, it will not quickly raise the chlorine level in your pool but rather will slowly dissolve and maintain chlorine levels with shock treatments of either liquid or granular chlorine to be added when required.

If you have any questions regarding your pools chemistry. Please feel free to contact me.

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