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Tuesday, January 8, 2013


Winterized Pool But Opened to a Mess?



                It is disappointing to open a pool after the winter and reveal a green pool with a black bathtub ring.  I have seen this occur more often in the past few years due to winterization kits that do not provide sufficient sanitizer and many times none at all.  It is common when purchasing winterization kits online and in discount stores that the oxidation product they sell does not contain chlorine but a non chlorine oxidizer.  Although the non chlorine oxidizer is a wonderful product for oxidizing wastes it does not leave a residual of sanitizer to combat bacteria and algae over the winter.   With no sanitizer in the pool it will enable bacteria to grow in a bio film within the pool, equipment and pool piping.  This bio film will then enable algae to grow as it is producing food for the algae as well beyond what the algaecide can handle.
Accumulated Oils at Waterline in Swimming Pool
 Here is a good way to imagine what is happening in your pool over the winter.  During the summer months your pool is used by swimmers with sunscreen, tanning oils and body oils.  These oils are in the pool water after use.  This can be compared to making a pot of soup.  Think of that pot of soup that is put into the fridge for storage.  It is not being heated to emulsify the oils nor stirred like circulation in a swimming pool.  The oils rise to the top of the soup or water base and form a ring around the edge of the pot.  This is what happens in a pool as well.  The oils accumulated around the edge of the pool are a haven for bacteria growth which consumes sanitizer.  Algaecide works with sanitizers to allow them to compromise the algae cells causing their death.  The result that occurs is algae in the pool and a bathtub ring around the winter water level.  Then the biofilm starts in areas that you normally do not brush in spring.  And they are smart (please read bio film hyperlink for further information).   This leads to reoccurring algae throughout the year. 
Decades ago when winterization kits were not available we closed pools with a super shock to raise the chlorine level to 5 ppm or higher and added an initial dose of algaecide.  We still had a bathtub ring from the oils.  The trend to a non chlorine oxidizer came about from a desire to lessen the bleaching of vinyl liners ( white concrete pools were shocked and this helped remove stains), and also the ability to ship non hazardous chemicals from internet warehouses.  However we have seen staining of pools from algaecides with metals and also bleached areas on vinyl pools (as well as blistered fiberglass pools) from floating tablet feeders that failed and sunk to the bottom or stayed close to a wall of a pool.  The chlorine tablets have a very low pH which can cause a  liner or finish to fail as it is so very acidic.  Also, the chlorine sitting on a pool liner will cause a large bleached area.  Floaters over the winter are advised to be used only in white plaster pools.
What can you do?  First of all add an enzyme to the pool to remove the oils and bathtub ring.  Many times adding a good enzyme will remove the bathtub ring without scrubbing within a 2 week period.  Also in the spring scrub under the ladder treads, skimmer throats and other areas of poor circulation and raise the chlorine level to 10ppm.  This will drop in a short period of time.  Add an initial dose of algaecide to your pool.  Be sure to clean your filter media with a product made to do this. 
Keep in mind that your filter media is taking out these oils all during the summer and the bathtub ring you see occur is intensified in your filter.  The use of an enzyme product during the summer will eliminate having to clean the waterline area of the pool, use less sanitizing and algaecide, and keep your filters cleaner giving you a carefree summer.
  Next winter use quality products that have a sanitizer, algaecide, and enzyme.