Planning on starting my tank up this weekend, which will be first (proper) planted tank. I cant really afford a co2 unit (i know there are diy jobbies, but feel these can be hard to manage) and i only have roughly 1.2 wpg - would co2 be essential? I apreciate plants would not grow as quickly etc, but as long as they at least help keep my stats in check, I'll be satisfied.