Okay so let me run this by you... Current tank: 20 gallon tall (not long) nano w/ a T5 two bulb setup, been up for 9 months. Upgrading to a 46 gallon bow front tank (picking up the tank tomorrow night) which will have an overflow box and 20 long for a sump setup. Want to run this tank with LED lights instead of T5's so thinking that I am going to buy one of your 16" setups, and in a few weeks adding a second one. ($360.00 total light investment). THEN, when my renovations are done at the house, I am going to add a new 125 gallon tank for the dining room. Having three openings up top (2 dividers, All Glass tank) would mean that each of these could go up on top of the 125, and if I add a third setup, would that be sufficient for a 125?? I am kind of looking at this from an investment stand point as well as functionality... I really do not want to buy a light setup or setups which I cannot use down the road, because the 46 is not my last stop - I will be adding the 125 probably late 2013, early 2014.