Hi, My CO2 is fed into the intake of a powerhead that I have blasting the mist along the length of the tank (powerhead output aimed roughly at the centre of the front glass). This results in a 'champagne' effect in my tank and most leaves in the tank swaying in the current - which I believe is 'what I want'. I have a 6' tank (400 litres) with 240watts of light over the top. Just last week I replaced the lights with brand new ones so I know my lighting is good. I am also dosing full EI, so nutrients good. Plant growth is still not real crash hot and there are various forms of algae popping up here and there. As Tom always suggests to look at CO2, and I believe I've ruled out light and nutrients as a factor, I am gradually cranking up my CO2. What is the best practice here? I am thinking the best practice is to: 1. Increase rate of CO2 slightly 2. Observe plants/fish for 1 week If plant growth/algae issues haven't improved and fish are ok repeat step 1-2 If plant growth/agae issues haven't improved and fish are gasping this means: - maximum CO2 is in the water back off CO2 slightly - issue with plants isn't CO2 related, i.e. CO2 ruled out by maxing it out If plant growth/algae issues improve after 1 week, stop. Scott.