I have been thinking about various ways to kill algae (regular green algae). Along the way I can up with three ideas that I think can help make the process simpler and more reliable. But they run against the common wisdom, so I thought I would ask for some comments and feedback to make sure I haven't completely lost my mind.
1) Wait till you are ready, don't just dump some bleach in and hope for the best. The typical advice is to get some chlorine in right now this moment and then add more as soon as you can. I think waiting till a weekend, or some other appropriate time, when you have enough chlorine on hand and can spend enough concentrated time to really deal with it is better. Too many people get into an endless cycle of adding chlorine once a day only to have the algae recover completely by the next day.
2) Make sure there is at least a little CYA in the water. The typical advice is to get some chlorine in there right now and deal with the CYA level when the algae is killed. Admittedly, it is difficult to measure CYA when the water is murky with algae and we don't want to add more CYA when the level is already too high. But often enough when people open for the spring the CYA level can be zero. If CYA is zero in an outdoor pool you lose chlorine to sunlight quite quickly. If sunlight drives FC to zero for several hours the algae starts getting ahead of us again and the effort and chemicals used to that point can be wasted. I think that adding 10 to 15 ppm of CYA, when there is any plausible chance that the CYA level is zero, could help.
3) Instead of testing FC and adding more chlorine to bring it back to shock level at least twice a day, how about doing that every half hour? I think Michael Silvester was on to something good when he suggested adding chlorine continuously until the water changed color. That doesn't sound quite right to me. Not everyone is going to judge color changes the same way. I worry about people using too much chlorine and possibly causing damage following his approach. What about going half way between the usual approach here (twice a day) and his: test and add chlorine every half hour? After a couple of hours of that the algae should be dead and the problem is solved.
I would appreciate any comments/feedback you might have.