Ozone, or O3 is active oxygen. It occurs naturally in the Earth’s atmosphere to protect us from the sun’s harmful UV rays. Ozone is also used as a water sanitizer, it has a neutral pH and does not add to your pool’s total dissolved solids - but it has limitations.
Because Ozone is a gas, it cannot touch every water molecule in your pool. It also has a short lifespan, lasting a very brief amount of time. Because of this it is often used in combination with chlorine. Much less chlorine is necessary however - typically about .5 ppm vs the usual 3-4 in a chlorine pool.
There are two types of ozone systems - those that use UV light and those that use corona discharge. I won’t get in the science of how these work here - but both systems install after your filter and pump, produce Ozone and inject it into your pool water which is returned to your pool. Typically UV systems are less costly than corona discharge units - so they tend to be more popular. Both are similarly effective at producing Ozone.
In sum, Ozone systems are a great option for pool owners who want to greatly reduce the amount of chlorine they use in their pools.
Commonly known by the brand names of Baquacil or Soft Swim, polyhexamethylene biguanide is a chemical that can be used to sanitize pools. In fact it is the only non-halogen sanitizer approved by the EPA for treatment of pools and spas. It is sold in liquid form and is added to your pool in much the same way as chlorine.
Biguanide alone is not enough to sanitize your pool. It is used in conjunction with algaecides and hydrogen peroxide or other formulations to treat your pool water. Manufacturers of Biguanide products typically sell systems that include the other items that you will need to treat a pool in this manner.
The main advantage of a Biguanide system is not having to use chlorine. This is therefore for people who cannot tolerate chlorine due to allergy or sensitivity or don’t like the smell or texture of chlorine. One other benefit is that Biguanides are not UV sensitive - so it does not become less effective with exposure to sunlight. Typically costs are similar between Biguanides and Chlorine systems.
Some of the cited problems with Biguanide systems are cloudy water, white mold, and pink slime. Also - there are reports that Biguanides can gum up your filter and plumbing - but products are available to alleviate this issue. Many users report that they don’t have these problems, but some do. Also, to test your water’s Biguanide level - special test strips are required.
There you have it - some alternatives to chlorine. Have you tried any of these alternatives? How are they working for you? Let us know in the comments!