Reasons behind draining a pool
Lower CH or CYA
Precautions
Please don't fully drain a pool, expecially a vinyl liner pool. Also be careful if it's really hot and you've got a plaster pool.
How do you drain a pool
There are multiple ways to drain existing pool water and refill with fresh water. Below are the most popular.
Lower Water then Refill
Drain alot of your water out.......then toss in a hose and refill.
No Drain Water Exchange
If you place a low volume sub pump in the deep end and pull water from there while adding water in the shallow end (through a skimmer or into a bucket on a step so you lessen the water disturbance) you can do a fairly efficient exchange. That is assuming the water you are filling with is the same temperature or warmer than your pool water. If your fill water is much cooler than your pool water, then switch it. Add the water to the deep end (hose on bottom) and pull water from the top step.
The location of the pump and fill hose may change if you have salt water, high calcium, etc. In my pool, with saltwater and high calcium when I drain, I put the pump in the deep end and hose in shallow end. The water in the pool weighs more per unit volume than the fill water from the hose.
Be sure to balance the water out and water in so the pool level stays the same. Also be sure your pool pump is disabled during this process. Once started do not stop until you have exchanged the amount of water you wish.
