I was thinking about something just like this the other day and i just so happen to see a post today about this product. I get the general idea of it but what I cant figure out is that it pumps pool water into it. If you are always adding pool water to it and not bleach wouldn't the FC level of it always be dropping?
Is it a good idea to get one? If I know my pool takes about X oz a day of bleach to keep FC at a 5 is there a number on the flow indicator that would be roughly that amount?