I currently have a 2 light setup on my 40g... 24wX2 life glo 6500k lights and a 20w single with a full spectrum. I run the lights for 8 to 10 hours a day. My question is if I would upgrade to a 150w mh would I have to use Co2 my plants are doing very well with the current light setup. The only reason I want to change is I also. Have a 30g that I am going to convert to a planted tank and I would use by current light setup on my other tank. Any advice here would be appreciated.