I don't know the dimensions on the tanks but make sure they are the same height.

I just worry about the tanks shifting and the glass breaking at the connections. Maybe someone will have something to say about this. You may have to hold each tank in place with wood trim around the base or countersink them individually into the stand so they will not move relative to one another.

I edited my post not realizing you asked about the sump in another thread.

Good Luck.