The biofilm should be cleaned out of you hot tub on a regular basis. Biofilm in the plumbing lines, tile line and filter harbor most of the bacteria and causes most all of the problems associated with hot tubs. Bacteria such as hot tub itch, pseudomonas, Shocking with chlorine won't work in that chlorine can't penetrate the biofilm's skin. UV and ozone won't work in that biofilm is stuck to surfaces. Ozone doesn't reach past your jets, and UV is only effective with the water that passes through the UV system. If you remove the biofilm from the spa and you will experience a much safer spa that is much easier to take care of. You will experience lower combined chlorine, less foaming, less chlorine usage, better smelling water, clearer water and most importantly, lower bacteria levels.
