Why Drain Your Swimming Pool?

One of the most common questions that I receive is “Why should I drain my pool and when do I do it?”
 
That is a good question a lot of folks have been misinformed as to why it’s so important and when this task should be done..
 
When should you do it?
 
Well, bluntly put, the water in this country (in most areas) is absolutey terrible.
 
In in most parts of the country October thru Febuary is the ideal time to make this happen.  If you reside in AZ or CA, you may need to wait until November or even December.

The outside temperature should not exceed about 75 degrees (or so).
 
If the weather is too warm, you run the risk of cracking the surface of your pool.  Not a good thing.
 
There are several reasons why you should be draining your pool every 2-3 seasons.  One of the most important is because of the TDS (total disolved solids) build up that takes place over time. 
 
Test TDS every 4-6 months – without exception.
 
Here’s a good example of “WHY”:
 
In the summertime, temperatures reach 100-120 degrees. Combined with low humidity and windy conditions the evaporation rate in your swimming pool is greatly excelled. When water evaporates, only H2O dissipates. The TDS remains in that body of water. The pool water is continuously replenished with fresh water supply through the automatic water fill. The water coming into the pool has a TDS factor. Thus a rise in TDS.
 
Example: Fill a quart container with water at 900ppm TDS. Evaporate 1/2 of that water from the container.  You now have 1/2 quart of water with the TDS factor of 1800ppm. Fill the container back to its original level with Distilled water (0 TDS), and you will have your original quart of water at 900ppm TDS. The water that is being used to replenish pools is not 0 TDS, but may have a TDS factor as high as 900ppm.
 
Perform the same experiment as before. This time, fill the container to its original level with water having 900 ppm TDS. You now have 1 quart of water with a TDS factor of 1350ppm. This is what happens in your swimming pool.
 
In addition to this, everything that enters the body of water; dirt, leaves, chemicals, bodies, ect….ect.

EVERYTHING has a TDS factor, which contributes to the overall rise of TDS in that body of water. In some regions, i.e.: coastal California, climate is not the main reason for a rise in TDS, rather chemicals being used. Calcium hardness, for example, is the main contributing factor in these regions due to use of Calcium and Sodium Hypochlorite.
 
When the TDS level of pool water rises, subtle problems will begin to occur: calcium deposits on pool at water line, brown manganese stains, salty taste to water, irritation to skin and eyes, etc.. As the TDS rises higher and higher, these problems amplify to a point where the pool will begin to deteriorate.
 
At high levels of TDS, calcium will begin to replace the plaster in gunite pools. This will expose itself as a dime sized circle on the plaster. At this point the calcium deposits at the water line will have grown to resemble a stalactite and manganese stains may be very evident.
 
The absolute maximum acceptable level of TDS is about 1500.  I prefer to keep it less than 1200.  When the TDS is extremely high, the water has a tendency to become “non reactive” to things that you’re putting in it (like acid and chlorine). 
 
Check this a few times per year and, if necessary,  drain your pool.  In the long run, this will save you lots of dough and headaches too.
 
Terry Duff
Founder  – FireYourPoolGuy.com