I'm picking up a complete 75g tank/stand/light and everything. The tank is 3 years established. There is a Fluorite substrate (unknown color). Will it be okay to mix in the new EcoComplete? There are 2 Discus, but I'll be passing them onto someone else that wants them. My plan is to have a school of green GloFish, a school of Glowlight Tetras, and one Striped Raphael catfish. I am undecided on which school of bigger sized fish. I may be getting a couple of Neon Tetras or Cardinal Tetras later on in the end. For now, how many of each, the GloFish and Glowlight Tetras? Suggestions for a bigger sized fish and how many? There's a strip light included, but it is 6.56 wpg. I do not know how many bulbs it holds, but if 4, I'll remove 2. If only 2, I'll replace them. My goal is to reach around 3 wpg (dont want to set up a pressurized Co2 system) and use Flourish Excel. Obviously I'll be having this tank planted. I'm undecided on which plants. I'll think on that some more. Merry Christmas (to me, too)!