In my 1 1/2 month observation you asked if I can go longer than normal with the Spa frog. I believe the answer is yes.
I soaked on Friday night, added 3 PPM chlorine and I just opened the lid. The tub was starting to get cloudy so I put in 3 PPM. That gives me another 1 1/2 days more than I get without. This was the first time I "measured" it but I'm going on a limb and saying it will give me some extra time. I will try it again to see if I get the same results.
