I have a 75 gallon tank with about fifteen rainbow fish. I've ordered
CO2 equipment which should arrive this week.

What's the best way to start this up? Do I just run it for brief
periods of time at first, like an hour a day, and gradually build it
up? I don't want to make any massive changes in the tank chemistry at
one fell swoop.

The pressure gauge I got has a solenoid, so I was planning to run on a
timer with the light hood, so the CO2 unit will ultimately be on for
about 9 - 10 hours per day. Mostly, I just don't want to come down
after the first day to discover 15 dead rainbow fish.

Currently, the tank contains several java ferns, two sword plants, a
micro sword, and an anubias.

Any tips from you pros would be appreciated,
Andy