Ozone Sanitizes Better than Biguanides
Some very prominent products on the market today claim to be ‘non chlorine alternative sanitizers’ that do not have the negative effects of chlorine but retain the benefits. Some of the most visible of these are based on ‘biguanides’, including Baquacil and Soft Swim.
The fact is that biguanide-based products are only partially effective against the range of contaminants likely to infect a residential pool. Ozone is effective against a wider range, and it is compatible with supplemental sanitizers that may be needed to protect the pool water when the pump is not running.
Do NOT Mix Biguanides with Chlorine
Biguanides are hydrogen peroxide derived oxidizers. These chemicals must NOT BE MIXED with chlorine – the chlorine will destroy the biguanide and produce unpleasant, milky water. If you switch from chlorine or bromine sanitizers to a biguanide, make sure to clean the pool very carefully, flushing all systems, to eliminate residual chlorine before introducing the biguanide.
The Pros and (mostly) Cons of Biguanides
- Biguanides can kill bacteria; however, they do not oxidize organic contamination like ozone does.
- To combat the organics buildup, biguanide systems need to be shocked periodically with very high concentrations of hydrogen peroxide.
- Because organics survive biguanide, microorganisms in the pool can develop resistance to it, rendering the sanitizer completely ineffective. (No organic molecule can ‘adapt’ to ozone.)
- Molds and slime based on these resistant organisms may develop in biguanide-sanitized pools. These pools need to be drained and then cleaned with chlorine shock – and then switched to easy maintenance ozone systems.
- Biguanides cannot be used together with ozone or chlorine.
- Biguanides are costly.
To summarize, biguanides are effective at killing bacteria, but they do not oxidize many other contaminants in the pool, including human fluids, lotions and cosmetics. Therefore, they need to be used with a supplemental sanitizer – but unfortunately, that can only be hydrogen peroxide at shock levels since biguanides are incompatible with chlorine, ozone and many other alternative sanitizers.