What is a bio film? A bio film is, to put it simple, a large amount of microscopic bacteria that builds up on practically any surface – especially wet and damp areas. And of course that fits the bill regarding swimming pools, doesn’t it? It also does not die under dry circumstances, but merely stays dormant until it water gets into contact with it again.
Where and how does it form? When wondering where bio film can be found in your pool, a myriad of places will come to mind. Every surface of your pool that comes into contact with water can be a breeding ground for bio films. This can be anywhere from your pool walls to skimmer baskets, plumbing etc. Bio film is formed under the right circumstances and the combination of a surface to grow on, water and microorganisms. It can grow in both fresh and salt water and generally only needs a little bit to thrive. Since bio film is not algae, it does not need sunlight to grow, and as long as the water is not too cold and it does not get brushed or vacuumed from visible places, it will continue to colonize and take over your pool. Your basic pool chemicals do not kill or prevent bio film. This is one reason for bio film flourishing in the plumbing system, since it is safe from being scrubbed off and the water is sometimes the best heat for them to grow in. As soon as you get rid of bio film, the amount of chlorine and other chemicals your pool needs, will drop significantly, since bio film is the biggest culprit when it comes to cloudy pool water.
How do I treat, get rid of and prevent bio film?
There are a couple of methods to remove bio film from your swimming pool and plumbing system.
The first method is by physically removing the bacteria. In all the visible places (which includes your filter cartridge, skimmer baskets, the pool surface, pool walls, etc.), bio film can be brushed or scrubbed off, or removed using a pool vacuum. Basically any surface that is easy to reach or that can be handled should be thoroughly cleaned. By brushing the bio film off of the surface, it is taken away from its optimal conditions and can then be killed by the chlorine and removed with the filter. (Just remember to clean the filter again from the “filtered” bio films.)
The second method you have, is using chemicals specialized in killing bio film. This will, more specifically, be inside the plumbing of the pool and heaters. This is where 99% of the bacteria grows and flourishes. You should contact your local pool center to get the best chemicals to remove bio film from the pool system. This is important, because bacteria can get resistant to certain chemicals, and you need an up-to-date pool expert to assist you with this problem.
Basically, if you get rid of and periodically treat your pool for bio film, you will extend the life of your pool and also use fewer chemicals. You will be able to balance your water more easily and won’t have to shock your pool as often.