I'm going to be adding sand to the 125 soon. I've had a hard time deciding what to do, but I think I'm ready to move forward.... 1.5 bags (75 lbs) of pool filter sand, 1 bag (20 lbs) of tahitian moon sand, and 0.5 bags (10 lbs) of moonlight sand. so it will be tan with some mixed in black and specs of white. I think that's a good ratio. Anyone have mixed sand tanks?