To maintain optimal water quality in your swim spa, you should clean the cartridge filter every two to four weeks, depending on how frequently you use the spa. Make it a habit to test the water daily and add a shock treatment as needed. Additionally, it’s important to check the pH and alkalinity levels on a weekly basis and adjust them as required. Aim to give your filter cartridge a thorough cleaning at least once a month. As for the spa’s acrylic shell, it should be drained and cleaned with a specialized, non-abrasive cleaner for acrylic surfaces at least once every quarter. Lastly, for the longevity and cleanliness of your swim spa, it’s highly recommended to drain and refill the water at least once a year.