I have a new Envoy which is 390Gal vs your Grandee 450Gal. My bather load is one person for two 30min dunks per day, Temp set to 102. I have the ACE set to 6 for the output level and the status stays within the green zone.- since its new to me I test a couple of times a week and have added only a few oz's of the dealer supplied dichlor each week - I plan to go the bleach as soon as i run out of the supplied dichlor. I did have to add 8oz of salt above the first load.