Maintaining clean and safe water for the users of our swimming pools, and aquatic facilities of all types, is the most important thing we, as facility owners, operators, and designers, can do.

Any aquatic facility that has lived through the nightmare of people getting sick, because of the water they came in contact with at their facility, can attest to the fact that constant water quality vigilance is an absolute MUST. (A recent article about an outbreak in the Cincinnati Area discusses such a nightmare.)

Note – If you really want to see statistics showing how common such outbreaks are, visit the CDC website for annual summary reports.)

The most important factor to maintaining clean and safe water is the type of equipment being used to treat and maintain the water.

When you have been an aquatic engineer as long as I have, you see a lot of products introduced to the market over the years. Although many of these products are introduced with great fanfare and slick marketing materials, the simple truth is that most do not perform as advertised. As a veteran designer in the aquatics industry, I have become immune to the hype and drawn to the effective.

Executive Summary

If your facility installs the following equipment, you can be assured you have the most state-of-the-art tools possible to keep your pool water clean and safe for your end users:

1. Great swimming pool water filtration, such as with regenerative media filters

2. UV treatment

3. Chloramine evacuator system (indoor pools only)

4. Chlorine water treatment (solid, liquid, or salt, combined with automated chemical controls and proper pH adjustment equipment)

With this equipment installed, and vigilance by pool operations staff at maintaining proper water chemistry balance, you will have the safest water possible for your swimmers.

The purpose of this article is to simply “cut to the chase” and lay out for you the true and proven state-of-the-art in swimming pool water treatment today. The following list represents the very best complete system you can deploy for the cleanest and safest swimming pool water possible:

1. Great filtration of the water

In the filtration category today, regenerative media filtration is one of the best available. It is not initially the cheapest, but it provides the best filtration possible at a low operating cost.

This filter will remove extremely small particles that are dangerous to swimmers and a cause of cloudy water.  The media used in these filters, perlite or diatomaceous earth (DE), is capable of removing particles as small as 1 micron from the water. Configured properly, this type of filtration is capable of removing many nasty microorganisms, such as the dreaded cryptosporidium.

Small particles that remain in the water are also costly because of unnecessary consumption of disinfection chemicals. Utilizing great filtration equipment will decrease chemical usage costs.

2. Secondary water treatment – Ultraviolet (UV) Light Treatment

Installing a properly sized UV system, in addition to a great filter, will effectively kill all of the nasty bacteria, viruses, and cysts that can make people sick. UV will also effectively break down chloramines that form in the pool water. UV is one of the best investments you can make in controlling sickness outbreaks at your facility while reaping a side benefit of maintaining cleaner water.

3. Chloramine air evacuation (indoor pools only) – Evacuator located near pool water surface

Since chloramines will form in the chlorinated water when people enter the pool, chlorine odor and equipment corrosion issues will occur. Even though a UV system will break down chloramines as they travel through the light chamber, chloramines will still form once the water re-enters a swimming pool with people in it.

The most effective way to prevent chlorine odor/sickness and equipment corrosion issues is to evacuate the contaminated air from a location just above the pool water surface and exhaust it outside of the building. An evacuator unit (installed as close to the water surface as possible) that is synchronized with the room’s HVAC system is the best way to eliminate offensive/dangerous/corrosive air issues.

4. Primary water treatment – Chlorine

No matter how you cut the deck, chlorine is the best primary treatment chemical for swimming pools. It really does not matter what form you use, calcium hypochlorite (solid), sodium hypochlorite (liquid), chlorine generator (salt), or chlorine gas (dangerous and hardly ever used these days), chlorine is relatively safe and stable for swimming pool use.

As a side note, chlorine concentrations lower than have traditionally been used are safe when all of the other systems described in this article are used. Many regulatory authorities have yet to officially lower chlorine residual requirements however, so you must follow the guidelines for your jurisdiction.