looking to get a new tank downsized from 150, torn between 75, 90 and 120, yeah the 120 is bigger but not sure. the 75 looks good for width and not too tall or should I go 125 72x 18w x22 my 150 was nice but too many scratches after 15 yrs use and I was Careful for the most part I like pristine tanks, IDea??