Shocking or Super Chlorinating your Pool?

The two can be confusing at times.  Some people don’t know when shocking or super chlorinating is needed; I understand and sometimes interchange the two myself.  Even though the two are very similar in all reality they are completely different.  I like to use the technical term break point chlorination when needed as not to confuse any customers. There is a lot to water chemistry and can become quite confusing.

Super chlorinating your pool is a term used to simply boost the chlorine level after a heavy bather load, and yes that means your dog, too.  One dog in your pool is like having 50 people swimming for the day.  The sign of algae, even the smallest amount would require you to shock your pool. You can find info on how to treat algae here If there has been rain all day or for some reason your chlorine level falls below normal.  I like to call that preventive maintenance.  These are just a few things in my opinion that could lead to more costly problems than to simply boost the chlorine lever by adding a couple of pounds of chlorine.

Don’t get confused when purchasing an item for either shocking ( break point chlorination ) or super chlorinating, because while each one does a different job the ingredient is the same, chlorine.   ( I’ll get into the different types of chlorine another day )

Shocking or break point chlorination is a whole different story and its job is completely different. You must consider the different forms of chlorine in your pool, before you can determine whether you need to reach break point chlorination.  It’s extremely important once you figure this out, that the right amount of chlorine is used or oxidation will not occur and you will create a much bigger problem.

Free chlorine –  This reading is what is left after the chlorine does its job and must remain at a residual of 1-3 ppm at all times.  Free chlorine is the sanitizing agent that keeps the pool free of any micro-organisms that could be present in your pool, causing you to become sick.  It also acts as a good oxidizer.

Total chlorine – The total chlorine is the sum of the free and combined chlorine.

Combined chlorine – This reading is the difference between the total and free chlorine reading.  It is considered the “bad” chlorine that has been used up by oxidizing organic matter.  Remember I said that free available chlorine acts as an oxidizer.  The best way to figure this out is to use a DPD test kit or you can bring a water sample to your local pool dealer.

How do we get combined chlorine and what is it?

Combined chlorine or chloramine is a chlorine by-product that is formed due to insufficient free chlorine. When the free chlorine is over powered by organic contaminants it can’t oxidize the pool water by keeping this matter in solution.    This will cause a strong ammonia like chlorine odor that most people think is too much chlorine, when in fact it’s not enough chlorine in your pool.  It will cause your eyes and nose to burn, and your skin to itch.   When this happens your sanitizer will become inefficient leaving your pool susceptible to many things like algae or a build up of micro-organisms.   It can also be the cause of a cloudy pool.  I could get into the technical chemical terms, but since this blog is basically meant for simplicity, I’ll stick to the basics.

How do you correct this problem?

You must reach break-point chlorination, which is 10 times the amount of the combined chlorine.  So if the reading is 1 ppm, then you need to add enough chlorine to reach 10 ppm.  Remember the combined chlorine is the difference between the total and free available chlorine.  Once break-point is accomplished all organic matter will oxidize or burn up, your pool will become crystal clear, and your free available chlorine will properly start doing its job.

Again I can’t stress enough how important it is to add the right amount of chlorine to reach break-point, if you don’t oxidation will not occur and could make matters worse.

Please if you have any questions feel free to ask.

What Causes Cloudy Pools

When dealing with most pool problems you should always start with the filtration system.  Let’s take cloudy water.  Oftentimes, cloudy pool or spa water is due to poor filtration or lack of sanitizer.  If these possibilities have been ruled out you may be dealing with a different issue such as suspended matter (chloramines) or as I call it organic junk.  This matter comes from swimmer contamination, dirt, algae, suntan lotions and oils, bacteria, minerals, metals, and organic matter.

Everything that is put into your pool or spa water is filtered through your filtration system or evaporated into the air.  Not every particle goes through this process and the ones that don’t are left behind.  Eventually, these particles build up over time to be what we call chloramines.  Chloramines  will cause a foul-smelling chlorine odor, poor disinfection, and eye and skin irritation.  All of this organic junk comes out of solution causing a cloudy pool.

When this happens you want to oxidize using a non chlorine shock or a chlorine shock to a break point that will bring the chloramines back into solution making your pool or spa water sparkling clear.

How do you know what the break point is.

You subtract the total chlorine from the free chlorine and times that by 10, and that is the ppm’s you will need to reach break point, bringing all the suspended particles back into solution.

For example if you total chlorine reading is 4.7 and your free chlorine reading is 2.7 then your combined chlorine reading is 2.0.  If you times that by 10, you get 20 ppm, and that is how high you need to raise your chlorine level to reach break point.

As always whatever product you buy always read the manufacturers directions first.