Cathie Bruen, a maintenance expert, states,
The biggest myth people have about pool care is that you need a chemistry degree. You don't. People have a misconception that pool care is way over their heads. But once you explain the basics to them, they understand. There are certain tasks that you perform once a week, certain steps that you must carry out more often. When pool owners have a problem, they can come into their neighborhood pool store with a water sample and with a list of chemicals that they have on hand, so we don't duplicate them. Once we get them on a regimen, and they stick to the regimen, it works (Anscombe, "Truth vs. Myth").
The chemicals that are needed are well-known and easily found, and the owner needs to monitor their use and assure that they are doing the job for which they are intended:
For tip top water, you need a sanitizer to disinfect and an oxidizer to break down cosmetics, oils, lotions and other unwanted materials that end up in the water. Sufficient levels of sanitizer must exist at all times to kill the bacteria and algae that thrive in a spa's warm water. Oxidizers, on the other hand, are usually added weekly, or after each use. For chemicals to work properly and to keep the water clear and comfortable, the pH must remain neutral. A spa's higher ratio of "people to water volume" can cause the chemistry to change more quickly than in a pool, so the water should be checked and adjusted more often (Anscombe, "Caring for Spa Water").
The use of chorine is well-established, but sunlight and evaporation can diminish the effectiveness of chlorine when it
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