I've written about this before and no doubt I will continue to write about it in the future. Flow rate in a CO2 infused aquarium needs to be high - it has to be in order to move around the fertilisers and CO2. What you want to see is your plants moving, swaying in the flow and if they are all doing that, then you've probably nailed it. But actions speak better than words.
Check this short YouTube clip out by Mark Evans - notice the powerful flow rate and also the excellent plant growth.
What's the flow rate like in your planted aquarium? Anything like Mark's?