wel im building a new nano... the tank is about 30L ish, iv had exactly the same tank set up for a lil while but not with much in it as i have always thought about improving it and wel i had anothr tank sitting around so thought i would do something with it, this tank is going to use a undergound filter with just under 1/3 of the tank acting as the filter crushed shell as bottom layer and coral sand on top, it is what is in my other tank and works fine. the improvements that i will make on this tank are that i am going to run pumps and heater inside a peice of pvc pipe that will run up the center of the tank so everything is hidden and will have a 360 degree view of tank, i will cover the pvc in live rock to create a sort of pillar in the center, the light tht comes with the tank is a 6w fluro but i am upgraing that to a 18w marine light and am going to make a wood base to hide underground filter and material on bottom. any coments or ideas would be greatly appreciated. i will post pics soon.