The answer is really a matter of personal preference. For a true, authentic wood fired hot tub experience we recommend an approach without chemicals, which allows the rich aroma of cedar wood and natural water feel to enhance the experience. This requires you to drain the water after 2-3 uses, wipe down the inside of the tub with a mild water/bleach solution, and refill it again for next time. The downside is, this creates a lot of wasted water and is not very sustainable (though if you can divert the waste water towards a garden, problem solved!). A fixed, electric filtration system is another option. Regardless, keeping your hot tub clean is hugely important, so if you can't change the water often, chemicals are your best route to maintain proper water hygiene and prevent the growth of bacteria and algae. Chemicals such as chlorine or bromine can be used to sanitize the water and keep it safe for use with regular testing. Additionally, pH balancing agents are also used to maintain the optimal pH level of the water. Some natural, eco-friendly products also exist, like Ahh Natural and Blue Magic, which are worth looking into. Alternatively, some users fill their hot tubs with saltwater for its therapeutic benefits as it's more gentle on sensitive skin and naturally relieves inflammation. To go this route, instead of adding the typical amount of chlorine to the water, you can purchase a sanitizing saltwater system that enhances the saltwater’s natural ability to create chlorine and purify the water.