Remove an end piece from each tank, align the two tanks on a flat surface (2 pieces of 1/2" plywood glued together to make a 1" thick piece the size of the bottom) as a base will do, as this is what you will be picking the tank up with) in a place where it won't have to be moved for a week.
Using the three 3" wide 1/4" thick pieces of glass I just described (I wouldn't do it without them again), that were cut to length to fit across the bottom and up the front and back sides. Silicone the two tanks together by their edges and tape together with fiberglass reinforced tape (doesn't stretch) and silicone the glass plates over the tank joints (from the inside) and clamp in place.
While this is curing, measure for a top cross brace and have it cut. It should fit inside the tank. After the third day of curing, you can install this cross brace with silicone.
The stress on the glass is no more that what it was before on the single tanks.
This tank is good for adding more small fish but you still can't have larger ones since the width hadn't changed.
Good luck and post pix if you decide to do it.
Dr Joe
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