As JasonLion said, algaecide isn't much help when there is already an algae problem. It is mostly useful as a preventative, but we don't really recommend it here. In fact I haven't added an algaecide to my pool in years and have had much better water quality than I ever did then.
Have you done much reading here, or is this your first visit to the site? If it is your first visit you may want to review this: What is Trouble Free Pool Care? It will give you an idea of what we do here and how we do it. A lot more information is available in the Pool School (the green link below) if you are so inclined.
Hi Janice, and what hasnt been mentioned yet is the TFP method of treating algae, which is called a SLAM. It is an ongoing process which is continued until the water is clear and testing confirms it. It is not just putting in "shock" once or twice, or adding some algaecide. http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl
Algaecide is best as a profit center for the pool store. The good ones have some use for winterizing. The bad ones don't do much except deplete chlorine, and the worst ones leave copper behind which gives you a bunch of green-haired kids.
Pool Store "shock" powders have their disadvantages, too. They either leave behind cyanuric acid or Calcium. Too much CYA will lead to what pool stores call "Chlorine Lock" and too much Calcium can lead to scale formation; sort of grow-your-own sandpaper on the walls.
"Shocking" your pool the pool store way generally doesn't work. Consider algae to be an infection. Chlorine is the antibiotic. The pool store will have you gulp the whole bottle of pills at once. Our way is to dose regularly until the infection is completely eradicated. To do it our way requires a proper test kit.
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Welcome to TFP! For a wealth of pool care information please check out our free Pool School. If you are in need of specific help then we encourage you to Register and ask us here in the forum!