It's a 50 breeder. It has a corner overflow with a 1 3/4 drain and a 1 1/2 return. But I Wana do the herby style overflow and use the 1 1/2 for full syphon and the 1 3/4 for the backup. Then that means I'd have tk drill the back glass as long as it is not temporal (wich I don't think it is).
I remember there was a discussion on rc about this tempered glass. Just because the panel has a hole, it does not mean the glass is not tempered. Also, there was a discussion about how to drill tempered glass....