Beautiful tank! I have been looking for info on removing the "rim" , can you share how you accomplished this?
There's a couple threads around here that I used for more detailed information. I can't find them offhand though. Just google search Rimless Bocube 29. Everyone said it would be difficult to do, but I really didn't find it too bad.
Here are the steps that I did:
1. Take a razor blade and run it under the rim on both sides of the glass all the way around the tank. This cuts the silicone and makes it ten times easier to remove.
2. I took a hand saw and cut the rim into 3 separate parts. Just make 2 cuts right before the corners on each side. Also make a cut on each side to pull the rim away from the base. Make sure you're careful doing this as the plastic is decently thin and you don't want to drive your saw into the glass. Once you get closer to cutting all the way through the plastic, you can take a butter knife and pry the plastic away from the glass to finish the cut. That's what I did.
3. Rock each individual side back and forth. Don't be afraid to use a lot of force. You'll have to pry the plastic off the remaining silicone. Eventually it should come loose. Do this to each piece, but be careful when you pry away from the corners as I've heard this is the most fragile part.
4. Take a razor blade and scrape the silicone residue off both sides of the glass. This is the most time consuming part.
A lot of silicone and plastic shavings will go into the water. I had my brother hold a net under the pieces that I was sawing and scraping in order to prevent most of it going in. Otherwise, you can turn off your pumps and the pieces will float, so you can just use a net and collect all of the pieces every 10 minutes. After you're done you can run filter floss to pick up anything that you had missed.