Borgthedog

I have a new hot tub (Caldera Kauai) and I am able to get an initial bromine level by using granular sanitizer (85% trichlor and 15% sodium bromide), which lasts for 2 days. I have an inline spa frog system that is then supposed to maintain the bromine level without the further need for granular sanitizer. I have now gone through two different bromine cartridges and I am never able to get a non-zero bromine reading beyond the intial 2 days during which the granular sanitizer is working. I am using oxidizer shock regularly, the water flows through the spa frog cartridge when I open the capsule, and the aquacheck test strips are working because they register bromine from the sanitizer. Please help - the dealer is stymied! Thanks!