Unfortunately, there is no magic way to turn a green or black pool clear overnight! It usually takes a lot of time, effort and money to clear up a typical "swampy" green pool. It is certainly best if you never let your pool water get dirty, however most pool owners experience a " green pool problem" from time to time.
Although it is not easy work, here is a proven method of clearing up a green, black or very dirty pool in the shortest time possible. Follow the instructions below for the best results.
Remove most of the large debris from the pool floor with a large leaf net (not a hand skimmer!) This will stir up the water; and may make your pool look much worse temporarily, but the stirred up debris will settle within a few hours. DO NOT ATTEMPT TO VACUUM THE POOL IF YOU CANNOT SEE THE BOTTOM OF IT, OR IF YOU HAVE A LOT OF DEBRIS ON THE BOTTOM. YOU COULD CLOG YOUR SKIMMER, FILTER OR UNDERGROUND PIPES!
Adjust the pH and Alkalinity levels of the water using pH plus powder, alkalinity plus powder and pH minus. These levels must be within the proper ranges or the water will never clear.
Shock the pool. This means super chlorinating the water to kill off any bacteria and algae. If your pool is very dirty, it may need MANY gallons of liquid chlorine (shock) over a period of days before the water clears. For most in-ground pools, start off by adding 3 or 4 gallons, and if you see no results overnight, add 3 or 4 more gallons the next day. Continue this process until you notice the water changing color to either cloudy white, light green or clear. The more you add the quicker it will clear! (Note… shock is available in liquid or powdered form, but we recommend using liquid (it works faster) and is safer if you have a vinyl lined pool). You may also want to add a high quality algaecide to the water at this point. If you have a sand filter do not exceed the recommended amount of shock, because it is possible to over-shock a pool and then you will need flock to coagulate (join together) the small particles in order to clear the water, because they will by-pass the filter. If you have a DE Filter don’t worry there is no such thing as over shocking.
Run your filter 24 hours a day and backwash your filter whenever the pressure reads 10psi higher than your starting pressure on your pressure gauge. Green or cloudy water will quickly clog a filter, therefore you may have to backwash your filter many times a day until the pool clears. THIS IS NORMAL! Remember that you cannot over-backwash a pool filter. The more you run pool, and the more you backwash the filter, the faster the pool will clear up. If you have a DE filter, remember to add new DE to the skimmer closest to your filter after each backwashing. A DE filter is a little more work than a sand filter, but the DE filter will clear a green pool 50% faster and more efficiently than the sand filter.
If you follow these instructions and your pool does not clear up within 4 or 5 days, your filter may not be functioning properly. If this is the case with your pool, have the filter system checked out by a professional. The pool will never clear up if the filter is not working properly!
Once the water does clear up, you will most probably see debris on the pool floor (dead leaves, algae, etc.). If there is only a small amount of debris on the pool floor, you should have the pool professionally POWERVACUUMED. This will save alot of wear and tear to your filter system, as well as assuring that no debris gets clogged in your pool pipes. If there is still large piles of debris, it use best to carefully try to scoop it out and wait for it to settle before attempting to vacuum to pool.