What a great thread! I'm hoping someone might be able to help me here. I have a 20 long and I want to try these lights. I'm using DIY CO2 and dosing liquid ferts. I'm trying to decide whether I want to get 2x 20 watt or 2x10 watt floods. Most of my plants are pretty easy going - Amazon swords, corkscrew vals, Anubis Nana, and some crypts - but I'm trying to fill in an area with glosso, and I understand that might need the higher light. I'm just concerned about too much light and not enough CO2. What do you all think?