Recommended flow rate?

[Barry Tetra]

So...as you guys may or may not know (from filter bacteria thread) I've been watching a lots of aquascaping video and tech lately and I've heard that the flow rate (either filter or power head) for the planted aquarium should be literx10L/H as you need to deliver nutrients and CO2 to the whole tank.

Here's my questions:
1. If I'm using diy CO2, how much flow rate would you recommend?
2. Most aquascapers used 2 canister filter to circulate CO2, how efficient is that?

 

[itiwhetu]

I have never used a flow rate as high as that for a planted tank. 4 times the volume of the tank, mind you I have never used CO2 and never used Ferts either.