Choose Ozone First, then (maybe) Add an Ionizer
Many people are choosing ionizers for pool sanitation to avoid the issues with chlorine. They have some good reasons to do this, but ionization has a couple problems too. The better choice, if you want to go with ionization, is to use ozone as the primary disinfectant/sanitizer, and then use the ionizer for residual sanitation.
Problems with Ions
Ionizers have a lot of attractive qualities, but a couple important drawbacks, too.
- Over time, ions can stain pool linings and walls. These stains are the product of basic chemical reactions, and not easily avoided -- or remedied.
- Ion systems can kill bacteria and algae, but they are NOT oxidizers like ozone. They do not kill the wide range of microbial organisms or neutralize the variety of organics (urine, lotions, cosmetics come to mind) that ozone does.
Despite these problems, ionizers running at a low level can be a useful way to provide residual sanitation that remains in the pool water. The normal option to this is to use chlorine as the residual (at a low level that most people do not notice or complain about), but if you are determined to eliminate chlorine (and we understand that motive), ions might work for you.
Ozone Systems Where Clean is Critical
The bottom line is that ozone is the best tool you have to ensure that the pool water is disinfected. The fact that ozone acts so quickly to kill or neutralize almost everything it touches does mean that it leaves little residual in the pump cycled water to attack foreign elements in the water. The real reason for a residual like ions or chlorine is that contamination can be re-introduced into water at any time. But neither of these can act as effectively as ozone to get the truly clean water you want in the first place.
For starters, you need ozone.