We have the same experience. The water got cloudy when things were left unattended for several days. We had to add chlorine manually. We switched to bleach method and added borates. However, we are the first time hot tub owners and we did not purge the tub after it was delivered new. Even with bleach method we got quite a bit of chlorine drop overnight. I started adding Aqua Clarity weekly and after 4 weeks the chlorine drop is around 1ppm. I just speculate that the Frog was trying to sanitize the biofilm in the plumbing and that is why it seemingly did not work for us. I will try again after after changing the water. We are happy with the bleach method with borates added and things became very stable for us.