Swimspa What Does O-Care Do To Help Me? O-care prevents biofilm build-up in your swim spa pipes, this will make your sanitiser (chlorine or bromine) more efficient and make your hot tub water better in general. Safe - Using O-Care can reduce the amount of chlorine or bromine used by 78%. This means a safer spa environment for your family. Soft - Softens your spa water, making your spa experience better, your skin feel softer after use and gives a more natural feel to your spa water. Simple - Just add 2 compounds to the spa water once a week using the measuring cup included. Another benefit of O-care is less strain on your pumps, filters and other components due to less biofilm build-up which leads to better and more consistent flow. How much do I need to use? Depends on the size of your swim spa. Each box will last 2-5 months depending on the water volume of your swim spa.