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Thursday, December 15, 2011

Giardia, The Most Common Pool Parasite is Not Your Neighbor

Giardia is a recreational water illness and is the most commonly found parasite in swimming pool water. This parasite can cause an intestinal illness in humans. It is possible to be infected even in a properly treated pool if the parasite is ingested before it has had adequate time to be killed. Casual contact of pool water into the mouth can ingest Giardia.

Although most bacteria are treated with recommended chlorine levels parasites like giardia are 15,000 times more resistant.

Giardia can be introduced into the pool water by fecal matter from infected animals or humans. It can take up to ten days for symptoms to occur after ingestion. Symptoms can be diarrhea, weight loss, fatigue, gas and bloating. It is highly recommended that people that have had diarrhea recently not use a swimming pool so that contamination cannot occur. However this advice of unhealthy pool behavior is not always followed placing other swimmers at risk. Persons with weakened immune systems and young children are at a greater risk of serious illness if infected with Giardia.


To determine if a swimming pool has Giardia you must take a water sample to a state or private testing lab. Testing for the presence of particular bacteria is not easily done by the pool operator so there are guidelines to be followed if a fecal accident occurs. If there has been a fecal accident in the swimming pool it should be treated properly according to guidelines set by the local bather code or the CDC. You must first determine if the fecal incident is a hard stool or loose stool as with diarrhea. Diarrhea usually occurs with a more virulent strain of bacteria so treatment for loose stools is much more stringent for chlorine level and concentration time of the chlorine to kill the possible bacteria.

Many of the pathogenic microbes are removed by swimming pool and spa filters but sand filters do not filter to a low enough micron to remove any of them.  DE filters and cartridge filters do the best job of removing microbes from the water.

Formed stools can act as a container for germs and removing them from the pool without breaking the stool apart can decrease the amount of bacteria released into the pool. In contrast a loose stool is more likely to contain bacteria and release them into the pool. Be sure to treat the stool removal tools so re-infection does not occur. It is not recommended to vacuum the stool from the pool.

If any type of fecal accident does occur you must first have all the swimmers leave the pool. This includes any pool that is on the same filtration system. If they are separate bodies of water but share the filtration system all bodies of water must be cleared.

For both formed stools and diarrhea, remove as much of the fecal matter as possible using a net or scoop device. Dispose of this matter into a plastic bag and use a trash container outside of pool facility to dispose in. Sanitize the net or scoop. You can place the net or scoop into the pool water while it is being treated.

We use a CT value which is the concentration time of free available chlorine in part per million (ppm) multiplied by the time in minutes. The CT value for Giardia is 45. Therefore if we take 45 and divide by 4ppm it would take 12 minutes to treat the pool with 4ppm of free chlorine.

For formed stools, raise the free chlorine level to 2ppm and adjust the pH between 7.2 – 7.5. The pH level is very important as it determines how active the chlorine will be. Maintain a free chlorine level of 2ppm for 30 minutes with the pool closed. 2ppm must be maintained until the end of the 30 minutes. Check with your local codes to see if they require any other times or chlorine levels. If there is a presence of chlorine stabilizers, a higher chlorine concentration may be required. Also increasing the chlorine level can decrease the amount of time for the pool closure or concentration time of the chlorine by using the before mentioned formula for CT value.

For diarrhea or loose stools we want to raise the free chlorine level to 20ppm and maintain the pH between 7.2 – 7.5. This will ensure treatment for more chlorine resistant bacteria if present. One of the most chlorine resistant bacteria is Cryptosporidium. Cryptosporidium has a CT value of 9600 and a free chlorine residual of 20ppm must be maintained for 8 hours to treat the pool.

The pool filtration system needs to be running during the treatment time. With diarrhea treatment the filter system needs to be backwashed or have the media changed if filter type requires such operation after treatment. Do not return the backwash water into the pool.

Swimmers can be allowed back into the pool once the CT value has been met and the chlorine level has been returned to normal operating range as allowed by state code.

If this is a public pool then a fecal accident documentation form should be recorded. This record should provide what type of stool it was and what treatment was taken as well as any other actions including disinfecting of equipment and filter cleaning. A log of the pool chemical parameters upon re-opening of the pool should also be noted.

Giardia and other harmful bacteria can be introduced to the pool at any time and the pool operator should always be knowledgeable and have the equipment to react quickly.
For more information:  CDC Giardia Prevention

Wednesday, December 7, 2011

Can Pool Chemicals be Added Through Skimmer or how to screw up a perfectly good pool.

Can Chemicals be added Through the Pool Skimmer?
To keep an inviting pool it is a necessity to add chemicals on a routine basis. These may be your sanitizer or balancing chemicals. Chemicals come in many forms and can be quick dissolving or slow dissolving. But many chemical solutions do not mix and can cause serious complications including equipment and pool damage as well as physical injury from combustion.
The most commonly used product that is put into a pool skimmer is chlorine tablets. This is done when there is no other chemical feeder installed in the pool system. Calcium hypochlorite tablets are quick dissolving and have a high pH so it is readily dissolved and only in the system a matter of minutes. However stabilized chlorine tablets commonly called Trichloro may remain in the skimmer for days or weeks. These tablets have a very low pH of 2.8 and can damage equipment making it brittle or erode even if the pump is running constantly. This is often why many pool heaters corrode and then the copper from the heater enters the pool and causes staining. If the pool is on a timer these tablets should never be used in the skimmer as a strong concentration of chlorine and low pH develops in a small area and can leach out onto the pool wall and into the equipment and valves of the system. Cartridge filters with a stainless steel rod in them corrode rapidly as well.
If cal hypo tablets and trichloro tablets are put into the skimmer together either on purpose or by mistake a chemical explosion could occur. It is always recommended to use a chemical erosion type feeder for trichloro tablets. A floater can be also used but they tend to float to one area and the same problem of concentration can occur. Also floaters are not recommended in vinyl pools or any color surface pools. If the floater breaks or fails the tablets can drop and bleach the area of the pool.
There is a trichloro product on the market in stick form that has a built in protector for when the flow of water is stopped in the skimmer to prevent the tablet from further dissolving. They are more in cost and are marketed more towards residential pools.
It is not recommended to use the skimmer to administer any chemical as the chemicals could be reached by bathers in the pool. This would not be safe and could cause injury.
Do not add “shock” products or granular /powder forms of chlorine to the skimmer either. These should be added to a bucket with water already in it and diluted before pouring around the edges of the pool. It is of the highest importance that these products be added TO water and never add water to the chemical as explosion will occur. Even a bead of sweat dropped onto a couple of ounces of calcium hypochlorite can cause an explosion. Always wear safety goggles as chlorine can do irreparable damage to the eye.
Dichloro, Lithium and Sodium Hypochlorite (liquid bleach) can be added directly to pool with caution. If any product falls to the floor of pool it should be brushed immediately. Liquid chlorine should be added from a close distance to pool water and around the pool perimeter. Also, take note of wind so that product does not blow out of pool or back onto you.
Most balancing chemicals for pH adjustment, total alkalinity, cyanuric acid and calcium hardness are added directly to the pool and brushed. Do not add in one area. Never add these products to the skimmer as they can clog the lines and also would react adversely to chlorine solutions. If calcium increaser is added in one area and not brushed it can form a hard mass that is next to impossible to remove. This can happen in the pool lines as well.
The pool skimmer is there to skim the top of the water removing debris and return water to the pump. Although it is inviting to use otherwise it is not wise and can be dangerous.

The picture above is of a 4 year old originally blue vinyl liner 25 mil. It was bleached, brittle and wrinkled under the skimmer area. Because his main drain line was connected to the skimmer it was the same around his bottom drain. This homeowner used chlorine Trichloro tablets in his skimmer and used a timer to turn his pump off for a period of time each day. This was a $3,000 replacement cost.

Tuesday, December 6, 2011

Keep Your pH in the Safe Zone!


 

Friday, December 2, 2011

Chloramines

How Chloramines Are Formed and the Best Way to Eliminate Them



Chloramines are a nuisance to swimming pool operators and users which need to be eliminated to assure a safe and inviting swimming experience. Preventative measures to keep chloramines at a minimum combined with adequate testing and corrective chemical action by the pool operator can avoid many pool problems resulting from their presence. New technology now enables the pool operator to control chloramines easier and more effectively.

Chloramines are formed when a halogen or chlorine based sanitizer is introduced into the water and reacts or combines with waste such as sweat, urine and ammonia to name a few. The chloramines compounds do not have an effective disinfecting ability and require one hundred more times the contact time to be as effective as free chlorine. These build a chlorine demand which must be met before a residual amount of chlorine or free chlorine can become present for disinfection. If the demand is not met with the amount of chlorine added then more chloramines can be formed.

Foul smelling odor, cloudy water, eye irritation, and skin irritation are a few of the problems that chloramines can cause. These are not desirable in any swimming pool environment and therefore must be controlled or eliminated.

Regular testing for combined chlorine indicates the presence of chloramines. Many quality test kits allow you to test for Free Chlorine then an additional Total Chlorine reading. Free Chlorine is the available chlorine to disinfect the water. Total Chlorine is all chlorine present in the water. To find the combined chlorine reading or chloramines in the water you need to subtract the Free Chlorine from the Total Chlorine reading with the result being the amount of chloramines or combined chlorine in the water. A reading above .2 of combined chlorine lets you know that treatment is needed. If you find that the level of combined chlorine continually is high in your pool then a change in the chemical maintenance may be necessary. This may change with temperature, bather load and other environmental factors.

To decrease the wastes entering the pool it is recommended for bathers to shower before entering the pool water. Although the wastes washed off of one person entering the pool may not seem like much when multiplied by many swimmers it can be a significant amount. Keeping pool decks clean and disinfected can also decrease the amount of wastes entering the pool. Having people that have recently had diarrhea not enter the pool for a period of time and having babies with diapers use swim pants also helps in preventative measures.

If chloramines are detected regularly it may be necessary to increase the amount of chlorine being generated into the pool to help meet the initial demand of wastes and decrease the frequency in which the pool must be treated to remove the chloramines.

To eliminate chloramines the pool water must be treated by raising the pool chlorine level or oxidizing the pool water to chemically break up the chloramines compounds. This is generally referred to as a “shock” treatment or super chlorination, when the free chlorine level is raised to ten times the amount of chloramines present. This has been the standard procedure for many years. This will eliminate the chloramines bond but also can leave high chlorine residual which must come back to normal levels before swimming is resumed. Recently the calculation for this has changed to account for the high chlorine level. Now we multiply the combined chlorine times 10 and then subtract the existing free chlorine reading. This end result is the amount of chlorine to be raised.

Recently there have been other options offered for chloramines removal. The use of a monopersulfate chemical which oxidizes the pool but does not leave a high residual of free chlorine is an accepted alternative. This is used on many “salt” or chlorine generation systems that do not have the ability of a boost cycle.

The use of ozone as a supplemental sanitizer has been shown to greatly reduce the amount of chloramines present in the water. Ozone does not leave a residual in the water but instead combines with the molecules to destroy or change them at point of contact. This contact point is before the sanitizer is added into the system. Therefore there is less waste to combine with the chlorine being addedafter oxidation. This in turn will create a lower chlorine demand for wastes before disinfecting the water. This is recommended also with chlorine generators to prolong the life of the cell.

UV light is effective in eliminating chloramines as it changes the molecules where they cannot reproduce and are then harmless. This method also does not leave a residual and is introduced to the pool water before the sanitizer is administered as in ozone.

Chloramines are the most important factor in pool water chemistry for the pool operator to be aware of and act upon. Eliminating wastes before entering the pool and regular testing of the water to determine chloramines levels are important to controlling the combined chlorine levels. Using a supplemental sanitizer to the system without raising the residual free chlorine would be preferable as many of these systems are more effective in treating chloramines and do not require a time of non swimming to let chlorine levels drop to an acceptable level. To be able to destroy chloramines on a continual basis with ozone or UV would allow for less sanitizer use and leave a safe friendly pool environment.

Friday, December 2, 2011

Chloramines

How Chloramines Are Formed and the Best Way to Eliminate Them



     Chloramines are a nuisance to swimming pool operators and users which need to be eliminated to assure a safe and inviting swimming experience.  Preventative measures to keep chloramines at a minimum combined with adequate testing and corrective chemical action by the pool operator can avoid many pool problems resulting from their presence.  New technology now enables the pool operator to control chloramines easier and more effectively.

     Chloramines are formed when a halogen or chlorine based sanitizer is introduced into the water and reacts or combines with waste such as sweat, urine and ammonia to name a few.  The chloramines compounds do not have an effective disinfecting ability and require one hundred more times the contact time to be as effective as free chlorine. These build a chlorine demand which must be met before a residual amount of chlorine or free chlorine can become present for disinfection.  If the demand is not met with the amount of chlorine added then more chloramines can be formed.

     Foul smelling odor, cloudy water, eye irritation, and skin irritation are a few of the problems that chloramines can cause.  These are not desirable in any swimming pool environment and therefore must be controlled or eliminated.

     Regular testing for combined chlorine indicates the presence of chloramines.  Many quality test kits allow you to test for Free Chlorine then an additional Total Chlorine reading.  Free Chlorine is the available chlorine to disinfect the water.  Total Chlorine is all chlorine present in the water.  To find the combined chlorine reading or chloramines in the water you need to subtract the Free Chlorine from the Total Chlorine reading with the result being the amount of chloramines or combined chlorine in the water.  A reading above .2 of combined chlorine lets you know that treatment is needed.  If you find that the level of combined chlorine continually is high in your pool then a change in the chemical maintenance may be necessary.  This may change with temperature, bather load and other environmental factors.

     To decrease the wastes entering the pool it is recommended for bathers to shower before entering the pool water.  Although the wastes washed off of one person entering the pool may not seem like much when multiplied by many swimmers it can be a significant amount.  Keeping pool decks clean and disinfected can also decrease the amount of wastes entering the pool.  Having people that have recently had diarrhea not enter the pool for a period of time and having babies with diapers use swim pants also helps in preventative measures.

     If chloramines are detected regularly it may be necessary to increase the amount of chlorine being generated into the pool to help meet the initial demand of wastes and decrease the frequency in which the pool must be treated to remove the chloramines.

     To eliminate chloramines the pool water must be treated by raising the pool chlorine level or oxidizing the pool water to chemically break up the chloramines compounds.  This is generally referred to as a “shock” treatment or super chlorination, when the free chlorine level is raised to ten times the amount of chloramines present.  This has been the standard procedure for many years.  This will eliminate the chloramines bond but also can leave high chlorine residual which must come back to normal levels before swimming is resumed.  Recently the calculation for this has changed to account for the high chlorine level.  Now we multiply the combined chlorine times 10 and then subtract the existing free chlorine reading.  This end result is the amount of chlorine to be raised.  

      Recently there have been other options offered for chloramines removal.  The use of a monopersulfate chemical which oxidizes the pool but does not leave a high residual of free chlorine is an accepted alternative.  This is used on many “salt” or chlorine generation systems that do not have the ability of a boost cycle.

     The use of ozone as a supplemental sanitizer has been shown to greatly reduce the amount of chloramines present in the water.  Ozone does not leave a residual in the water but instead combines with the molecules to destroy or change them at point of contact.  This contact point is before the sanitizer is added into the system.  Therefore there is less waste to combine with the chlorine being addedafter oxidation.  This in turn will create a lower chlorine demand for wastes before disinfecting the water.  This is recommended also with chlorine generators to prolong the life of the cell.

     UV light is effective in eliminating chloramines as it changes the molecules where they cannot reproduce and are then harmless.  This method also does not leave a residual and is introduced to the pool water before the sanitizer is administered as in ozone.

     Chloramines are the most important factor in pool water chemistry for the pool operator to be aware of and act upon.  Eliminating wastes before entering the pool and regular testing of the water to determine chloramines levels are important to controlling the combined chlorine levels.  Using a supplemental sanitizer to the system without raising the residual free chlorine would be preferable as many of these systems are more effective in treating chloramines and do not require a time of non swimming to let chlorine levels drop to an acceptable level.  To be able to destroy chloramines on a continual basis with ozone or UV would allow for less sanitizer use and leave a safe friendly pool environment.