The nights start getting a little cooler (40 degrees or less), and pool owners recognize it as the first sign that the season is preparing to change. The days warm enough to swim reduce gradually until they regularly are out numbered by the days that are too cool to swim. At some point, it can no longer be denied, the pool season is over!
When it's time to get ready to close up your pool, taking the time to do it right will prevent problems during the winter and help avoid delays opening the pool when the warm weather returns. About three days to a week before you will close your pool, begin preparing it. Adjust the water chemical balance to the following ranges:
pH: 7.2-7.6
Alkalinity: 80-120ppm
Calcium Hardness: 180-220ppm
Reduce filtering times gradually over a week
Once this is accomplished, shock the pool, following the package directions. When the chlorine level is 1.0 to 3.0, winter algaecide can be added and it won't interfere with the effectiveness of the algaecide.
To avoid damage from freezing and/or snow, these items should be removed from a pool and stored for the winter:
Skimmer baskets (all pools)
Wall fittings (all pools)
Cleaners (all pools)
Ladders (above-ground pools)
Decks and rails (above-ground pools)
Solar covers (all pools)
Some pool covers require the water level to be lowered. Check the pool cover manufacturer's recommendations. Use a submersible pump or the filter pump to lower water level if need.
Remove all plugs from equipment like pumps, heater, and chlorinator. Completely drain all equipment. If needed, blow out equipment so there is no water left to freeze and cause damage to the pool equipment. When possible, remove the pump and store indoors. DE filter grids and cartridges will need to be removed and cleaned. It is recommended to lubricate all o-rings and for gas heaters with cast iron plugs it's a good idea to lubricate the threads.
The pool should be as clean and clear as you can make it. If you have been properly maintaining the pool, it shouldn't be much work to skim and vacuum the swimming pool.
For in-ground pools if you can't blow out the lines, add antifreeze, following package directions. Once lines are safe from freezing, install expansion plugs. For above ground pools, the lines can be disconnected. Putting large air pillows in an above-ground pool will help protect the liner.
When the pool is clear and the water is clean and at desired chemical levels, it's time to cover it. A properly fitting cover is essential to proper pool closure.