First off.that is WAY too much Chlorine to be adding. 1-2 ounces is plenty depending on the use and number of users in the spa at a given time. The Vision caretridge when used in conjunction w/ D-1's Ultra-Pure water mgmt system will allow you to significantly reduce the amount of chlorine you have to use in your lotus bay. We always recomend using chlorine 1-2 times a week, and shock with 1-2 ounces of Non-Chlorine shock after using.
As for when you have to take the vision cartridge out:
We recommend adding stain & scale control/metal control upon fresh filling the spa, and then waiting a period of 48 hours before adding any chemicals to it. You shouldn't have to use clarifiers with vision either, as clarifiers tend to aid in the removal of minerals from the water. Also whenever you remove the vision cartridge you should keep it in a bowl or a bucket of water, b/c it gets wet it must stay wet. I hope this helps you.
Jason,
Store Manager for a D-1, Caldera, Nordic and Hawkeye Spas Dealer