My last 2 tanks have been corner pentagons, the first was a 95 gal and my current is 150 gal. I had my top made with euro bracing and I have no problem reaching any where in the tank. Even with out the Euro top I have had no problems with reaching the tank. The only negative I have found is trying to get the flow to hit every spot, but with proper planning I have got it covered just like I like it. If you have any questions just let me know and I will let you know what I have learned.
Chris