Mike,
You can also do a little prophylactic "near-shocking" before pool parties or other high chlorine demand events. In your pool, adding 1.5 -2.25 gallons of 6% bleach (2-3 3 quart jugs) will increase your free chlorine by 3.3 to 5 ppm which, in conjunction with your normal SWG production, will probably be enough to handle all the stuff that 15 or 20 bathers introduce and still leave you enough residual to keep the algae at bay until your SWG catches up the next day.

Also, most SWG manufacturers recommend 60-80 ppm CYA. I'd bring it into that range unless yours recommends something different.

Lastly, if your brown patches are leaf stains, shocking the pool will usually get rid of them. I get those in my negative edge trough from oak leaves and acorns and a jug or two of bleach in there for a couple of days erases the stains.