What is a biofilm and what can I do about it if it has formed in the raw pipes of the whirlpool?
Bacteria are relatively harmless when they occur on their own. They can be killed off very easily using disinfectant. This is why you produce a type of mucous that entraps them. The Biofilm.
1) Biofilm is a thin, viscous layer of organic substances that clings to the inner walls of plumbing. - The adhesion prevents it from being rinsed away.
2) Biofilm consists of polysaccharides. These polysaccharides are insoluble in chlorine or bromine.
3) Grime (e.g. soap residue, body oils, etc.) as well as hard water deposits (e.g. calcium, lime, etc.) also become trapped in the biofilm.
4) Biofilm occurs in various forms from thin and viscous to stone hard. That is a question of age.
5) Living in the biofilm are bacteria, amoebas, algae, and fungi that are resistant to disinfectants
6) At the boundary layer of the water, parts of the biofilm and/or bacteria etc. get deposited into the water time and time again.
7) Since the biofilm is resistant to chlorine, it grows incessantly.
8) Biofilm is capable, for example, of absorbing and metabolizing chlorine. So, bacteria can even feed off of chlorine (i.e. "chlorine demand", which can cause a rapid decline in chlorine in the Whirlpool).
9) Biofilms are resistant to UV disinfection (ultraviolet light) and silver ion disinfection as well.
Biofilm can also appear in new Whirlpools. These biofilms form due to leak tests conducted in the factory with “compromised” water (i.e., water used over and over again). Upon emptying, up to 40 liters of water can remain in the internal plumbing. There it putrefies and forms into biofilm.
Those quote-on-quote "new" Whirlpools can sit for weeks in transit in hot containers (in the summer) and then be kept in storage warehouses or put on display somewhere before it comes to you. For that reason, you should always use Lotus Clean Shock right when you get a new Whirlpool.
Lotus Clean prevents the formation of biofilm due to dirt and bacteria and can entrap and filter away oils and hard water deposits as well. It can also stunt and halt the grown of biofilm that has already formed. Nonetheless, Lotus Clean Basic was not designed to remove biofilm.
With existing biofilm, Lotus Clean could potentially cling to the biofilm and entrap it against the pipe wall. Hence, substantial flaking could occur if the water flow strips off shards of the entrapped biofilm.To remove biofilm, you can use Lotus Clean Shock. Shock dissolves the polysaccharides existing in the biofilm. That can take a few weeks, however, if the biofilm is very old, solidified, and thick. When removing the biofilm, it is advised to start with a basic Whirlpool cleaning using Lotus Clean System Wash and Lotus Clean Shock. Then, follow up with more frequent Shock treatments until the biofilm itself has completely dissolved and disappeared.