Very funny these little colored dots at the bottom of the bath! When bonded they do not detach easily (unless it is obviously doing well but it does not slip !!). The red has a heat indicator (HOT) that appears when the water is too hot, perfect for bathing small (and larger :)). Cleaning level is like everywhere, after a certain period of use it starts to blacken between the suction cups but a flick of sponge or bleach and hop bath, like new!