CO2 is going to be a use or don't use thing. As in, everyday or don't use it at all.
With that said. If you use pressurized, you can turn it off at night. That would be the exception to running or not.
I don't have much experience with plants yet. So don't take everything I say as completely failsafe, right.
And now, with that said.
I've been reading about it off and on for years. Mostly in forums like this.
The one thing that seemed necessary, was to have enough light to be able to watch the plants grow. As in, enough growth to hender algae, and remove nitrates.
I've found this to be far from being a fact, now that I've done some growing myself.
My first, real planted tank, was my 30g, 36"L tank.
It's primary purpose, was to grow snails(food) for my brothers puffers. So I had nothing to worry about, and had a good opportunity to try some plants.
I got every type(about 5) of plant my LFS had.
Put a 96w CF + the 30w florecent I already had, over it.
Had about an inch layer of Seachem Flourite, plus another inch or so of plain 'ol aquarium gravel over that.
The bottom of the lights, sitting on the glass top. Were about 13 1/2" from the gravel.
I was using DIY CO2 run through a PH.
Not much at all for water movement in the tank. And basically nothing at the surface.
I wouldn't recommend this with fish present.
But I'm sure it kept alot of co2 In the tank, for the plants.
Yea, thats alot of light. And I'm sure if we used that, weatherman, heat index. Those plants were feeling 5-6 wpg.
But I think I'm trying to make a point here. lol
Below are some pics of start and finish of that planted tank. The plants(at finish) went into the 55g, in my sig.
Full shot from start-up. 2-23-09
Here is a pic I have of the right half of the tank, pointing out some anacharis growth. It started out as a hitch hiker. That inch tall plant inside the 3 squares.
2-23-09
Here is the same right half 2 months later on 4-21-09
With that said. If you use pressurized, you can turn it off at night. That would be the exception to running or not.
I don't have much experience with plants yet. So don't take everything I say as completely failsafe, right.
And now, with that said.
I've been reading about it off and on for years. Mostly in forums like this.
The one thing that seemed necessary, was to have enough light to be able to watch the plants grow. As in, enough growth to hender algae, and remove nitrates.
I've found this to be far from being a fact, now that I've done some growing myself.
My first, real planted tank, was my 30g, 36"L tank.
It's primary purpose, was to grow snails(food) for my brothers puffers. So I had nothing to worry about, and had a good opportunity to try some plants.
I got every type(about 5) of plant my LFS had.
Put a 96w CF + the 30w florecent I already had, over it.
Had about an inch layer of Seachem Flourite, plus another inch or so of plain 'ol aquarium gravel over that.
The bottom of the lights, sitting on the glass top. Were about 13 1/2" from the gravel.
I was using DIY CO2 run through a PH.
Not much at all for water movement in the tank. And basically nothing at the surface.
I wouldn't recommend this with fish present.
But I'm sure it kept alot of co2 In the tank, for the plants.
Yea, thats alot of light. And I'm sure if we used that, weatherman, heat index. Those plants were feeling 5-6 wpg.
But I think I'm trying to make a point here. lol
Below are some pics of start and finish of that planted tank. The plants(at finish) went into the 55g, in my sig.
Full shot from start-up. 2-23-09
Here is a pic I have of the right half of the tank, pointing out some anacharis growth. It started out as a hitch hiker. That inch tall plant inside the 3 squares.
2-23-09
Here is the same right half 2 months later on 4-21-09
Gotta be bored to come up with that idea. 
