A gunite swimming pool is one that has walls made from cement and then coated with a layer of plaster. This type of swimming pool needs to be winterized before the cold weather sets in so that there will not be any cracks that form in the plaster and cement. Of course, if you live in an area of the country where it does not freeze, you do not have to go through all of the operations. However, it is important to keep an eye on the temperature and decrease your use of the pool.
Step 1: Test the Water
It is important to test the pool in the water before doing any winterizing to it. If you do not completely drain the pool in the winter, then it is going to have to be treated so that excess algae, mold, or other germs do not begin to grow. Use a common swimming pool test kit and a sample of the pool's water. Go by the manufacturer's directions when testing the pool water. There should be a reading of 7.2 to 7.6 pH and about 2 parts chlorine in the water. You may need to add the balancing chemicals in order to get the water right.
Step 2: Shock The Pool
Once you have the pool water just where it needs to be, then apply some pool shock. This should be applied while the pump is running so that it is circulated evenly throughout the water. Let it run for about 8 hours.
Step 3: Use Algaecide to Treat Water
After you have given the pool enough time to circulate the shock in the water, apply some algaecide. This will help the water also fight off the growth of algae while the pump is not running during the winter.
Step 4: Backwash Pool Filter
Set the pump to backwash the water so that it will clean out the pump and the filter. You should let this operation run for about 3 to 5 minutes depending on the color of the water. Once it clears up you can then turn it off.
Step 5: Drain The Water
With the pump and filter drained and clear of any water, set the sump pump below the surface of the water. Set the drain hose away from the pool and let the water drain out. You want to drain the water to about 6 inches below the skimmer. If there is tile in the gunite swimming pool, then make sure to drain the water below the level of the tiles. This will ensure that they do not crack from the freezing water.
Step 6: Drain Water From Hoses
Use a shop vac to blow out the water from the pool hoses. Once they are clear of any water then you will need to use some water plugs to stop any water from entering the lines.
Step 7: Cover Gunite Swimming Pool
Use a durable pool cover and spread it over the length of the pool. Secure it so that it can not blow away. This cover will keep anything from blowing into the pool or damaging it from falling ice and snow.