Slow water movement...as slow as possible.
if the tank is a matured one, no worries about debris or algae. it doesnt matter if the difuser is at the corner of a big tank... co2 will get to the plants. just because you cant see this happening with naked eyes doesnt mean its not happening.

Hands up ...if any of you guys actually find any sucess in using fast flowing waters.

btw creeps ..on your point 7 about dosing ferts when plants are awake, remember i once mention fert dosage only goes in during daylight hours and got plenty of objections from the sifus..one even went as far as saying dosage only at lights out..hehehe...seems you are catching up on the game huh. well, an old man's word will not carry any weight unless one tries out for themselves. hahaha

__________________
Everyone Has a Photographic Memory..........some just dont have film!