My Name writes:

So, my question - Is my family going to swim in
emerald green water all summer as a result? Has anyone thought of
doing
this?

I used to follow the "run during daylight" doctrine.

Then I thought, why not let the stuff grow in the daylight, and give it
a whallop of filtering and chlorination at night, when the chlorine
isn't dissipated by sunlight. In theory it should sterilize the pool of
both microbes and algae during each night, and algae can't really get
going too much from zero in one day. And nighttime chlorination is so
much more effective, more sanitizing power per dollar, than during the
day.

Now this won't do for a public pool where you have to keep the water
sterile during daylight usage. You gotta have chlorine and filtering
then to take care of all the "cheek wash".

But it certainly works well, and economically, for my residential pool,
to run only about 6 hours from dusk. On occasions when there is
daylight bathing load, we turn it on manually.

(This is a pool with a chlorine generator.)

http://www.truetex.com/poolcontrol.htm