Replace your Aqua-6 and Aqua-8 Ozone Generator's diffuser stones and tubing as needed. We recommend replacing these at least every 6 months to a year. Make sure to select the 1" stones and Aqua-Series tubing sizes. Also chose the 1/4" check valves. Also, if you are buying tubing by the foot, please include the number of feet you want. We also carry replacement parts for the Aqua-Series. If you need any assistance, contact us.