If you want to use the stand you have for 2 tanks all you need to do is build a support of the middle section. 2x3 from the homedepot, you can have them cut them to the size you need. the top piece should be full length, then minus out the with of the top piece so your support arms rest flat on the floor. screw it all together when you get home, and put your tanks on it. A very simple project. or you can place them on the floor, if they are going on carpet I recommend a piece of plywood an inch wider then the tanks, carpet could put extra stress on the bottom glass.