Increase free chlorine in a pool by adding 1 pound of chlorine or bromine for every 20,000 gallons of water. You will need to purchase the appropriate amount of chlorine or bromine for the size of the pool. This process takes under 30 minutes, but the material should circulate overnight.
- Test for free chlorine
Use a free chlorine test kit to determine the amount of free chlorine in the pool. Follow the manufacturer's instructions to read the results. Free chlorine levels should range between 1 and 3 parts per million. A strong chlorine smell is an indication that free chlorine levels are low.
- Measure the appropriate amount of shock material
Calculate how many pounds of shock material you need to use by measuring 1 pound of chlorine for every 20,000 gallons of pool water.
- Add the shock to the pool
Sprinkle the shock into the pool at the end of the day. This will give the shock time to raise the free chlorine level without it being burned away by the sun. Don't cover the pool.
- Brush the pool
Brush the sides and the bottom of the pool to remove any debris.
- Run the filter
Allow the filter to run, circulating the chlorine until the next morning.