Posts Tagged ‘chlorine demand’

Managing Pool Water In Extreme Weather- Some Important Things To Know

Bob Russell | July 13, 2013 in Pool,Pool chemicals,Pool Service,Sanitizers,Uncategorized | Comments (0)

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2013- A Summer of Extreme Sanitizer Demand-

 

Q: “How did I wind up with algae in my pool when my chlorine levels have been perfect!”

A: Chlorine demand is a term service providers use to describe a pool’s specific sanitizer requirements. It is a term we must consider in extreme weather- chlorine demand is a concept that helps us prevent pool water going from clean to green- something that can occur in a very short time during extreme weather conditions.

As the term implies, sanitizer requirements will vary. We tend to adjust our sanitizer feeder equipment to “normal” and forget about it. The purpose of this post is to help you understand when “normal” sanitizer settings will not maintain sanitary water- under certain extreme conditions a pool’s sanitizer level can drop from ”ideal” to zero in an hour.

So far, this summer has included some of the most difficult “chlorine demand” challenges I have ever seen. The following events are examples of things that can dramatically change chlorine demand; my goal is to help you recognize when something is happening and prevent problems:

  1. Hot weather
  2. Heavy rain
  3. Wash-in: Heavy rainfall shedding off lawns and gardens can contaminate pool water with organic matter and fertilizers.
  4. Heavy bather load- such as one might see at a holiday party that features swimming.

The Perfect Storm: This summer has included some long periods of hot weather: we have experienced frequent heavy thunderstorms with local torrential rainfall; add to all this a holiday party around the pool and the “normal” sanitizer levels are overwhelmed. Once sanitizer levels drop to zero a pool water is no longer sanitary for bathing- under these conditions water can cloud quickly and develop significant algae problems- often clouding within 24 hours. Pool Owners should also realize that pool water doesn’t cloud immediately once sanitizer hits “zero”-  it is during this period that water- even though still clear,  should be considered a potential health concern.

One fairly common health issue associated with swimming in pool water without proper levels of sanitizer is an ear infection- nicknamed “swimmers ear.” Such health issues are easily avoided if you understand extreme ”chlorine demand” events and conditions and take precautions.

Recognize “Chlorine Demand” and Make Adjustments: Here are some things you can do to prevent losing the use of your pool for a week (or longer)- this is about the length of time it can take to recover and clean up from an algae outbreak or clouded water:

  1. Test water more frequently as chlorine demand conditions rise. You will “see” your sanitizer disappearing when you test and be able to make some good decisions before water clouds. You don’t have to be a certified water chemist to know the condition and quality of your pool water. Consider purchasing some good quality dip strips- this 5-second test is easy and gives you early warning to head off cloudy water and algae before it happens.
  2. Inform your service provider if you are planning a party. There are preventive things that can be done to handle the increase in bathers. It may be as simple as adjusting sanitizer feeder upwards and monitoring levels periodically. Normally a service provider comes weekly and balances the water and sanitizer levels. The point of this post is to help you recognize events or conditions that occur between visits that may be having a big impact on the water.
  3. Recognize when a heavy downpour may have introduced garden or lawn material into your pool- Fertilizer not only ties up pool sanitizer but at certain levels can render it ineffective! We will discuss how to remove Phosphates and Nitrates from pool water in another post; but you should be aware of any wash-ins and inform your service provider if this happens.
  4. Prevention is far easier- Preventing an outbreak of algae or clouded water is far easier and less costly than treating it. Clearing a cloudy pool or killing an algae bloom can be very expensive not to mention the disappointment of not being able to use the pool. Green water is probably the #1 or #2 reason why pool service providers are fired. The other reason being a slow response time. When sanitizer levels “crash” and water begins to cloud or algae has gained a foothold- time is critical.

In our upcoming blogs we’ll discuss some of the specific challenges presented by automatic pool covers and address bather issues such as sensitivity to chlorine or bromine.

 


Pools And Heat Waves

Bob Russell | July 9, 2012 in Equipment maintenance,Pool,Pool chemicals,Pool Service,Uncategorized | Comments (0)

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Heat Waves:

Every pool owner should understand two basic concepts about their pool during a heat wave:

1) Chlorine demand (or which ever sanitizer you are using)

and…

2) The Petrie Dish 

Chlorine Demand is basically the understanding that it will take more chlorine to maintain a sanitary and clear pool under certain conditions. Chlorine demand increases during a heat wave because the things that “spend” chlorine tend to increase- these include: increased bather load; heavy thunder showers (including wash-ins); higher temperatures.

The second concept of the Petrie Dish helps the pool owner understand and visualize that without a sanitizing agent present in the water, algae or micro-organisms can grow very fast.

In the “perfect storm” of heavy bather load, thunder storm and high temperatures a pool can go from the ideal of 3.0 ppm chlorine to zero in a day. Generally a chlorine feeder cannot recover to 3.0 ppm by the time algae or micro-organisms have already started to multiply. Once plant and animal life has been established in a swimming pool, the chlorine demand can double or triple quickly. Unless you intervene, you will have a real problem and it all can happen in 24-36 hours.

Here’s what you can do:

  1. First, understand these two concepts. Awareness that something is happening before the pool is green, or someone gets an ear infection is best.
  2. Adjust chemical feeders to handle an increase in bathers.
  3. Careful with use of time clocks! I see this all the time- a pool owner trying to save $100. on their monthly electric bill winds up spending $500. to kill algae that has gotten out of hand. Chemical feeders are only adding sanitizer to pool while pump is running.
  4. Check pool water after a heavy storm or a pool party. This, more than anything, will help you understand chlorine demand and keep you aware when you need to do something between normal weekly service visits.

Enjoy!

For more information about pool and spa service, check out “Water Blog” on our website!: www.glengatecompany.com


Hazy, Hot and Humid!

Bob Russell | June 1, 2011 in Pool,Pool chemicals,Pool Service,Sanitizers | Comments (0)

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Sanitization Basics:
You should know these two concepts:
1) Chlorine demand
2) The “Petri Dish”

Chlorine counts can drop dramatically during very heavy bather use.

Chlorine Demand:
When I teach new pool owners about sanitization, I look to make the complex simple. The chemistry behind sanitization is complex. Understanding a principle like “chlorine demand” is easier than trying to understand the science behind it (although understanding the science is helpful if you’re in the pool business).
Chlorine demand is self descriptive. How can you recognize chlorine demand increases? Here are a few things a pool owner should watch for:
1) Increased bather load (number of swimmers)- swimmers (and pets!)  introduce things like ammonia into a pool which complicates chlorination and increases chlorine demand..
2) Water Temperature- high temperatures increase chlorine demand.
3) Sunlight- UV causes established chlorine counts in a pool to deteriorate. To minimize the effects of sunlight on pool sanitizer, “Chlorine Stabilizer” is added (also known as Cyanuric Acid).
4) Wind and Rain- Both introduce contaminants into pool water. Whether wind-borne pollen and debris or waterborne pollutants, both interfere with chlorine effectiveness or just use it up.
This past weekend, many pool owners turned on their heaters, the weather was hot and humid, the pools were used- a LOT; and we had some storms. It was a weekend of very high chlorine demand.
This is why many pools get algae shortly after Memorial Day weekend- chlorine settings that could handle a chilly, unused pool were not adequate to handle a warm and well-used pool.
Think about chlorine demand and you’ll anticipate these things and save yourself a lot of problems.

Pools on the coast have unique chlorine demand challenges:

The Petri Dish:
High School Biology taught me this principle: Introduce animal or plant life into a sterile environment with food and you have exponential growth. This is how you should look at your pool. What prevents the growth of things like: plant life (e.g. algae), Bacteria (e.g. E-Coli) or Parasites (e.g. Cryptosporidium)?
A: Your sanitizer does.
Example: When chlorine levels are at zero, one algae spore can turn a pool green (what is called an “algae bloom”) in about 36 hours.
Using these two principles will help you anticipate changes and prevent problems.
Enjoy the pool!