If your max depth is 30ft and you're in a Jon boat, this unit is overkill for you. Get the unit that is black and white and structure scan only.
For that matter, get a Lowrance X65(I think). Its a standard sonar and not structure scan but I have one on my trolling motor and love it. I use the Elite unit for GPS mainly and for a higher definition view vs standard sonar. Its not going to give you amazing structure images as advertised though. My screenshots look good but I expected more from it. Just my opinion. I wouldn't spend that much money on a sonar if its only for 30ft max. My lake gets up to 180ft with 50-80ft average and 20-30ft is shallow to me. At 10-20, I'm almost on the bank unless I'm on a shallow flat.