I'm not sure what you're trying to ask, however a 20 long is actually 30" long, not 24". A tank that is 24"x12"x12" is a 15 gallon.

So was the question about whether or not you could make a 40 gallon out of two 20 gallons? Yeah, you could, but it might be a pain, and it will not be durable. Chances are the first time you try to move it without extra hands it will seperate, but if it's going to stay in the same place for a while you could do it. You have to start by removing the silicone holding the sides together, and then you'll need to cut the plastic braces. You might be able to find a way to connected the plastic braces of both tanks (metal brackets) which could reinforce the tank. Then you'd need to apply aquarium sealant to the seam. In the end you would end up with a tank that measures about 12" tall, 12" deep, and 60" wide.

Is that what you were getting at?

[ Show Entire Thread ]