Essential Chemicals
There is one and only one chemical that stops the pool from going green, and that’s Chlorine. It's the most commonly used element to eliminate bacteria globally and is also odourless.
The smell comes from what is known as Dead (Combined) Chlorine, which forms when free chlorine interacts with organics. If it builds up faster than it oxidises (leaves the pool), it will start to decrease the efficiency of your chlorine. You can get rid of it by:
- Shocking the pool with free chlorine (10x the level of dead chlorine).
- Adding an oxidiser (non-chlorine shock).
Maintaining the pH level is also crucial for chlorine to function effectively. Chlorine has a very high pH level of 13.0, causing it to lose effectiveness when it enters the pool. To balance the pH, Hydrochloric Acid with a low pH of 1.0 is used.
- At a pH of 7.2, chlorine is 62.5% effective.
- At a pH of 8.8, chlorine is 9% effective.
In Australia, 80% of pool owners use a salt/mineral chlorinator to generate chlorine. Salt is used to create chlorine with a salt cell, reducing costs and providing stable chlorine levels, plus they're fully compatible with minerals.
Long Term Chemicals
Long-term chemicals save time and reduce costs. For example, Alkalinity, which is actually just baking soda, stabilises pH fluctuations and protects pool equipment from corrosion.
Stabiliser (Cyanuric Acid) binds to chlorine molecules, protecting them from UV exposure.
Calcium prevents equipment corrosion and surface damage. Lack of calcium can lead to issues such as surface damage or leaching (white protruding stains).
Specialty Chemicals
Phosphates from organic debris, urine and practically anything alive can lead to algae growth. Phosphate removers like Starver help prevent this under the right conditions.
Alternative sanitisers like Copper eliminate bacteria and harmful pathogens. Minerals like Magnesium, Potassium, and Boron improve water quality and feel.
Other Pool Needs
For cloudy or green water, clarifiers help the filter collect fine particles. Flocculants bind sediment and drop it to the bottom of your pool for you to vacuum out.
Pool surfaces affect chemical needs. For example:
- Vinyl and fiberglass pools don't need nearly as much calcium.
- Concrete foundations require higher calcium levels (200-400 ppm).
Spas are maintained differently, using bromine instead of chlorine.