Hey i had a 4g emersed tank with UG. Its now filled with water and has pressurized CO2, 26w. The day after i filled it i noticed there was a small outbreak of BGA on one side. Why would this of happened? The BGA is spreaded and getting worse. I will suck it out today but i want to get to the bottom of it so i doesnt return. Im normally used to dealing with it in reef aquariums.. butnot sure what causes it for freshwater.