Bacteria and Biofilms in Your Swimming Pool

by Pool Builders on 02-17-2014 in Articles

Bacteria in your swimming pool:

To begin, what are bacteria? Bacteria (the term bacteria is used in this article to cover all micro-organisms, whether they are bacteria or viruses) are naturally occurring biological organisms that are microscopic in size. Bacteria are everywhere: in the air we breathe, the water we drink, on the surfaces we touch. Most bacteria are not harmful, but a few are. Bacteria are transported from one place to another very easily and conveniently many times via YOU! Most bacteria prefer to live in colonies and so they prefer surfaces where they can congregate and multiply. Most bacteria are also fairly "smart" in that they know how to naturally protect themselves against even chemical intruders that are applied to destroy them. Like us humans, bacteria want to preserve their lives!

The other thing you have to realize about most forms of bacteria is that although small, bacteria are really rugged and resilient to not only their environment but also against anything that may come against them. This is especially so of the virulent pathogenic types. Many bacteria can actually live in some of the harshest environments known to exist. We humans would need the most technologically advanced environmental suites just to survive. And so we have to know where bacteria live and breed and how they survive hiding from most of our water care and treatment. That's what the scientists at the universities and laboratories jobs are for: to provide the information we need to understand what we're doing and saying.

Probably the single most significant thing that we've learned about bacteria and their growth in the past several years from several university studies is that bacteria in swimming pools is not just floating around in the water looking to be taken out and killed by chlorine, bromine or other pool water sanitizers. The bulk of bacteria in swimming pools are actually found in something called a "biofilm".

Biofilms are exactly what you'd expect them to be: a biologically-based film. These biofilms are found on almost any surface in any place. If the place happens to be warm and moist, so much the better! With that in mind, we now know that swimming pools are literally lined all over the place with biofilms: on the pool surface itself, at the waterline, in and on the filter and its media, in the piping and plumbing lines. The worst part is that most of these areas are almost completely inaccessible to direct cleaning making the biofilms close to impossible to remove.

Keep in mind that biofilms are literally everywhere. The most "familiar" biofilm you encounter is the biofilm mass on your own teeth! Although you may brush three times a day, that nasty, sticky film grows right back onto your teeth all day long. If you don't brush and remove that film regularly, that film becomes plaque and tartar which are not only really difficult to remove but in time contribute to tooth decay and disease.

A similar thing happens with the biofilm on your swimming pools surfaces and plumbing. Instead of cavities and decay, our pools and equipment have a shortened life and will build up unsightly scale and stains. You should also know that these biofilms have an incredibly low pH - under 1.0 - and therefore can significantly contribute to problems with long term water balance.

And so, we partially control bacteria at its source by removing biofilms. Biofilms on all of the pool's surfaces (seen and unseen) contain up to 99% of all bacteria in swimming pools (Center for Biofilm Engineering, State University of Montana). By breaking down and removing the biofilm we eliminate areas where bacteria (both pathogenic and non-pathogenic) can hide, grow and populate or multiply. Understanding that only between 1% and 5% of bacteria is "free-floating" or "planktonic" brings the realization of how little sanitizer (regardless of type: chlorine, bromine, Biguanides, copper sulfate solutions, ionizers, etc.) may actually be needed in treating and sanitizing pool water.

We also understand that biofilms will and do absorb chlorine, bromine, copper and other chemicals and elements into the biofilm rendering those sanitizing agents completely ineffective. Biguanides, although not entirely absorbed, are rendered ineffective by simply "attaching" to the biofilm - rather than doing their work "floating" in the pool water attacking and trapping bacteria and algae, the long-string biguanide molecule is stuck onto the biofilm adding to the biofilm's stickiness and even "strengthening" it by becoming yet another layer.

As we remove the biofilms, we control the amount of bacteria that is present in the pool water. The good thing is that biofilm is very easy to accomplish by using safe and environmentally friendly salts and silicates and enzymes. Salts and silicates remove the biofilms from their surfaces, enzymes help to consume and completely remove them from the pool. Simple weekly additions is normally all that is necessary to do the job.

Minimal sanitizing - perhaps biweekly or even monthly depending on the preferred sanitizer - may be necessary and at significantly lower levels than otherwise historically maintained. Chlorine (especially Free Available Chlorine - this is the chlorine that is most effective in killing bacteria and algae) levels of less than 1.0 ppm (minimum of 0.5 ppm) or Bromine levels (less than 2.0 ppm) should be more than sufficient to properly control bacteria.

What else do you end up with? Many customers report a cleaner pool, cleaner filter, simpler water balance (pH, total alkalinity) and even nicer feeling water. And that's why you have a swimming pool in your backyard to enjoy.

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