I honestly have no idea about C02, I have never used or know much about it. I usually keep my tank about 79-80⁰F. I used to get constant staghorn algae before I got a siamese algae eater than cleaned everything spotless! I use Seachem Flourish and it has almost every micro element I would say, but I dont believe it has any micros. Currently all that's in the tank is 6 gold tetras, 4 guppies, an oto, an albino bristlenose pleco and a siamese algae eater. Since my discus moved tanks the levels in this tank have been so easy to control im just confused about it. The light that I have has a 24 hour cycle but is off for probably 5 hours or so, but it has a very slow sunset and sunrise. I have another light of the same size and brand, just a little less fancy so I have to have it on a timer, but while it is on it is 100% brightness. I also have always used RO water and have recently heard of remineralizing only recently and wonder if not doing that could also be causing me problems? I originally had my extra lighting to grow some guppy grass crazy fast, but I thought Val was able to handle a wide variety of light conditions. I am also honestly bad on being consistent with my fertilizing, but since I just got the val and have only dosed once with it, I don't know if my fertilizer melted it or was totally unrelated. I try to clean up extra food pretty quickly also since the tank is a little understocked currently and will vacuum up all the poop my pleco leaves if I notice any buildup fairly fast.