I'm trying to setup the Pool Math iOS app. When I tell it I'm using a SWG (salt water generator), I can't find mine listed (2019 Hotsprings Flair hot tub). I tried to figure out how many lbs of chlorine output my tub has, and it appears to be .02-.03. However, I can NOT add the number into the calculator. Am I doing something wrong, or is the salt water portion of the calculator not for hot tubs?