Nothing is more disturbing than green pool water. Not only is it unusable, it’s environmentally dangerous and just plain ugly. Here, you can read about what causes it and what clears it.
Causes of Green Water
Green pool water starts out from algae growing on a pool’s floors and walls, and if left untreated, it will turn the actual water green as well. In the latter case, you’ll find green material floating all throughout a pool’s depth. And it occurs from a lack of adequate chlorine. You may be surprised at how quickly green swimming pool water can form. Depending on the size of a pool, the algae in green water can bloom within less than a week. In any sized pool however, algae will almost always occur after chlorine levels fall lower than 1 ppm (parts per million).
Shocking a pool is the only remedy for curing green water. Shock is a high concentration of chlorine that will kill algae and any other organic element much faster and more effectively than normal levels of chlorine will.
Merely dumping a bunch of shock into your pool won’t solve the problem however. You’ll need to make sure that you use the proper dose and that you’ve attacked all the algae that’s present.
That means you’ll need to brush the walls and floor of the pool first to dislodge algae stuck to the pool’s surfaces. You’ll then need to run your filter to help catch some of the algae that you’ve dislodged. After these tasks are completed, superchlorinate, i.e. shock, the pool with 10 ppm for slightly greenish water up to 25 ppm for water that is solid green.
Allow the filter to run for at least 12-24 hours and periodically check its cartridge. Continually remove algae from the filter’s cartridge during the entire process.
If you don’t notice a significant change within this time period, add another bucket of shock-water solution. You’ll know that your solution is effective when you see floating white matter or grayish “gunk” on the pool’s floor. This is dead algae and though much of it will be filtered, you’ll need to vacuum the rest of it from the bottom. Failing to remove dead algae will only create an environment for new algae to grow.
Once the pool’s chlorine level achieves a range within 1-3 ppm, it’s safe to swim.