I've got a 75 gallon corner tank, it's 26 inches deep and from the front of the glass to the back corner is 25 inches. I just stand on a step stool and I don't have any problems with it. I'm only 5' 6" so it's not like I'm a giant person. I really love the tank. I've also got a standard rectangular 55 gallon tank right next to it but I love the look of the corner tank much better.
The only problem I had was figuring out how to make a canopy for it. I finally managed though after I found my protracter so I could figure out what angles I had to cut the wood at.