I BUILT A STAND FOR A TALL 30 GALLON ALL I DID WAS MEASURE THE SIZE OF THE TANK AND MADE A SQUARE THE SAME SIZE, THEN I MADE A LARGER SQUARE THAT THE SMALLER ONE FITS INTO. THIS WILL HIDE THE AQUARIUM MOLDING. YOU CAN NEVER OVER BUILD A STAND SO DON'T SKIMP ON THE SUPPORTS.
HTH