Fresh Air – Fresh Water

We have been “circling the wagons” with the “pool atmosphere” concept for quite a few years now. Now there are literally a dozen or more “expert” opinions on water and air quality and almost all of them have some good points. At the present time over 50% of the facilities department’s “please solve my problem” type calls have to do with poor air quality. The information listed below is written in lay-persons terminology and may help you investigate and solve your specific problem.

First & Foremost: Air Quality and Water Quality are dependent on each other. Air quality will be affected by:

Ø The amount of fresh air that is being introduced into the building every hour. A 90% change of air every 20-25 minutes works well.

Ø The condition of the air handling equipment filters. The filters should be cleaned or changed every 3 months. There are micro-filters that filter out more air-borne contaminates than the standard fiberglass or paper filters.

Ø The type of air handling system you have. Electric heat offers more dehumidification than gas. Do you have a Desert-Air type system and is it regularly serviced and working properly?

Ø Routine maintenance must be done and tracked on all pieces of air handling equipment. Vents and louvers must be checked and lubed at least 4 times a year to make sure they are working properly. Motor belts and fuses also need to be checked.

If the air smells like chlorine – something is wrong. That acrid smell we sometimes associate with chlorine is usually ammonia. In the swimming pool industry the “cause of this odor” is called “chloramines”. Chloramines (combined chlorine) occurs when free chlorine combines with ammonia and other nitrogen compounds. This “combining process” can be accelerated by perspiration, urine, saliva, body oils, lotions and some shampoos/soaps, fertilizers, and many industrial or household cleaners. The odor is created when water is not properly balanced . The odor intensifies when swimmers agitate the water – as in kicking or general warm-up swimming. The odor is worse at water level but can be extremely irritating at deck level or in the viewing area. Many times not only an odor is noticeable but eye irritation is also experienced. Sometimes the water may be hazy – but not always. Many times, the water will appear perfectly clear and the water test for free chlorine and pH reads normal.

This has become such a widespread problem in indoor pools that literally hundreds people are hospitalized each year. People with Asthma can find themselves in Intensive Care if exposed to this type of pool condition for even a short period of time. Most of the problems occur in indoor pools. Outdoor pools have plenty of fresh air and sunshine (ultra violet light) so they are not as susceptible to the chloramines problem.

Chloramines formation can be accelerated by:

Swimmers not properly showering before entering pool.
People using the pool rather than getting out and going to the restroom.
People doing a high level of aerobic activity and sweating in the water. (everyone sweats in the water – the same as if they were doing exercise on land)
Residues from ammonia based cleaning products that are used on decks or in shower rooms/lavatories.
Residues from fertilizers used on landscaping (nitrogen based) that gets tracked into building on everyone’s shoes.
Poor air circulation and fresh air introduction into the pool building.

So – what do we do if this occurs ?

Let’s divide the answer into 2 parts:

short term solution
prevention

SHORT TERM SOLUTION:

If Chloramines are detected the most prevalent solution is to “shock” the water. This means super-chlorination (break-point chlorination) or raising the level of chlorine in the pool to 10 parts per million. Normally a dry chlorine powder or a liquid chlorine is used to achieve super-chlorination. Recent studies show that many times this is not as effective as Hyper-chlorination which is raising the level of chlorine to 20 parts per million.

These methods may “burn out” chloramines but will also necessitate the pool being closed for a few days. More than the normal amount of fresh air will also have to be introduced during this process.

Some success has been realized with a non-chlorine shock additive. Adding an Oxidizer (Potassium Peroxy, Monosulphate = brand names Oxykleer or Oxybrite) to the water to convert the available chlorine to free chlorine can release the available chlorine to free chlorine. If this process is done in the evening, swimmers can usually be in the pool the next morning. Fresh air introduction is still important.

PREVENTION:

Usually more than one thing needs to be changed to alleviate the problem.

The most common methods are:

1. Change the air circulation system to include more fresh air introduction and better turnover.
2. Evaluate the type and brands of chemicals being used to treat the pool water for both chlorine and pH control
3. Evaluate the pool filtration system to see if a filter that filters down to a more effective micron rating (like DE at 4 microns) would help.
4. Check the labels on all cleaning products to make sure they do not contain ammonia or are not nitrogen enriched.
5. Have you staff attempt to get the users of the pool to take showers before entering – this is usually required by state health codes.
6. Consider installing an Ultra Violet (UV) water treatment system that cuts down on the amount of chlorine you have to use and also “breaks down” chloramines.

When does the pool water need to be changed?

That depends on:

The size of the pool
The water temperature the pool is kept at
The bather load
The type and brand of chemicals used
The type of filter and the turnover rate

In general – the smaller the pool the more frequently the water has to be changed. Hot Tubs in the 300-600 gallon range need to be drained and refilled at least monthly. Many State Dept. of Public Health’s require that exact schedule.

Many specialty pools – such as lessons pools or therapy pools in the 1,500 to 5,000 gallon range need to be drained every 3-4 months. The warmer the water and the higher the bather load the more frequent the water needs to be changed.

Larger pools – such as lap pools and competitive pools can actually go years before needing to be drained. Because of the large surface area of these pools exposed to evaporation, new water is constantly being added. In effect the water is always in a state of renewal. I have seen pools with perfect water that have not been drained for 4 years or more.

Some things that can shorten the life of the water and necessitate early draining:

Improper chemicals with non-soluble buffers or binders and poorly designed “inert ingredients”
Poor quality filtration
Continually “shocking” pool to break up chloramines
Users not taking showers before entering pool

Problems cannot be ignored. Serious health and safety issues are involved. Everyone who works in an aquatic facility needs to be made aware of the importance of a clean and healthy environment.

mnelson@usaswimming.org