Yes, there are alternative chemicals to chlorine available, bromine and Baquacil (PHMB). They each have their own challenges, however, and we don’t really recommend them. Read below to learn more.
Bromine
Pool bromine is a sanitizer, oxidizer, and algicide that is used in swimming pools and spas as an alternative to chlorine. For pools, Bromine is mostly sold as solid tablets, granules, and sticks with a few liquid options. Bromine and Chlorine are both part of the same family of chemicals known as halogens and share a lot of similarities, but also some differences.
Bromine eradicates contaminants by ionizing them, or forcing them apart at the molecular level. Bromine lasts a little longer than chlorine does, but it also works slower than chlorine does, taking longer to destroy contaminants. Because of this, a common practice is to use both chlorine and bromine to sanitize a pool.
Bromine performs better at higher temperatures and pH than chlorine, making it a popular choice for hot tubs and spas. However, bromine is sensitive to sunlight and less effective when exposed to UV rays. Bromine is also not as good as chlorine at oxidation, or breaking down contaminants in water. Bromine is hard to acquire, and therefore expensive. Another thing to note is that once you change your pool to a bromine pool, it will be difficult to convert it back to a chlorine pool.
Baquacil/polyhexamethylene biguanide (PHMB)
Baquacil is the brand name of a preservative-free polyhexamethylene biguanide, or PHMB. Baquacil is a chlorine-free liquid sanitizer that provides safe, consistent control of bacteria and algae. Originally developed as a surgical disinfectant, it is a non bleach/halogenic product whose main oxidizing component is hydrogen peroxide. It has a long shelf life, is highly stable in water and lasts longer than chlorine without any of chlorine’s unpleasant side effects.
Baquacil completely replaces chlorine, but it doesn’t oxidize the way chlorine does. This means it won’t kill bacteria, algae, and other contaminants that are vulnerable only to oxidation. You must use an oxidizer with PHMB, and ideally a separate algaecide as well. If you use Baquacil instead of chlorine, you must use Baquacil brand oxidizers and algaecides. They’re created to work specifically with the sanitizer. If you do not use these additional products, your pool will likely become cloudy and contaminants can build up. You can, however, use other brand of chemicals to balance your pool’s pH, alkalinity, and calcium.
When balanced properly, Baquacil is an effective chlorine alternative, but is more expensive than chlorine and much more difficult to maintain. In the long run, converting to a salt system will be easier on your wallet.