I decided to make myself a feeder breeder tank. I took 2 old ten gallon aquariums I had laying around unused and I remover the black plastic rim entirely from the top and on one of the long sides on the bottom of each. Which took a while in and of itself. Then I took a razor blade and cut a line down the inside silicone seam of the long wall that has the plastic removed from the bottom. Then Took said razor blade and wedged it in the seam and slowly ran it down through the entire seam. Then made a few more slices down the length of the bottom seam (insurance haha) and laid down the wall and cut the remains of the seam and removed the wall. I did this to both tanks, so what I have is two 3 sided 10 gallon aquariums. My plan is to clean up all of the edges and attach them together making a (nearly a square) 20 gallon aquarium. I am going to cut pieces off the glass walls I removed to reinforce my new silicone joints. Then I am going to try to use some of the plastic trim from the top to reinforce the corners from the top. I am using an aquarium safe silicone from petsmart. Hopefully it all works out! I know it won't necessarily be pretty but it will hopefully hold water. i want to breed convicts in it and use them as feeders. Easy and disease free, and free fish because I catch my convicts. How clean do the areas I am caulking need to be (can there be a little residue from the previous silicone?)? Any suggestions or opinions? Will my plan work?