Ignore previous post as I think I am muddling through. Here's another related question. I reviewed the thread about my previous efforts to get rid of algae. Quick recap: in process of shocking, and after turning off SWG, FC test results were:

4/11/12, 5PM, FC =15.5
4/12/12, 6AM, FC =14
4/13/12, 7AM, FC =10
4/13/12, PM, FC = 8
4/14/12, AM, FC = 7
4/14/12, PM, FC = 7
4/15/12, AM, FC = 7
4/15/12, PM, FC = 4.5
4/16/12, PM, FC = 7.5
4/17/12, PM, FC = 9.5
4/18/12, PM, FC = 8
4/19/12, FC = 10.5
4/20/12, PM, FC = 8.5
4/21/12 PM, FC = 7
4/22/12, PM, FC = 4.5 (I turned SWG back on at this point)
4/23/12, PM, FC = 5 (I added 48 oz. of CYA, don't know if I added bleach)
4/25/12, PM, FC = 11.5 LEFT TOWN
5/4/12, PM, FC =10
5/5/12, PM, FC =9 (added 48 oz. of CYA)
5/6/12, Am, FC = 8
5/7/12, AM, FC = 6.5
5/7/12, PM, FC = 6
5/8/12 I"VE GOT ALGAE FOR SURE!
5/8/12, PM, FC = 6.5 and shocking starts

Also, re: test results, just fyi, when tested during shock period, CC was always .05, < .05, or 0.

As I said in previous post, it is clear to me now that I didn't keep FC > 15 long enough.
So, here's my thought/question:

**** Can algae, over time, raise its tolerance to FC? That is to say, if you don't get all the algae when you shock (due to human error or whatever), at some point in time after repeated unsuccessful attempts to shock, will the FC need to be maintained > 3 - 5 ppm in the future to keep algae at bay? I am not a chemist (obviously) and have never had much interest in chemistry but am somewhat fascinated by all of this.
An aside, it seems like there could be some really interesting science projects out of pool water study. I'll have to remember that when my grands are a little older