I finished my MS in mathematics 5 years ago. Over these years I have been teaching at a community college (primarily calculus 1,2,3 with analytical geometry and Ordinary Diff. Eqs). When I was in my masters program I was having trouble narrowing my interests and decided to stop at my masters and start teaching. During this time as an instructor I have become very interested in some applied mathematics (biology in particular). I plan to apply to several PhD programs in the near future. With that said, I didn't keep in touch with too many people from the university I attended. I did stay in touch with a couple of my professors (on a minimal basis) and plan to ask them for letters of recommendation.
Would a letter of recommendation from my department chair at the community college be of any advantage (and even suffice as 1 of the 3 required)? Or should I call a professor from 5-7 years ago that may remember the grade they gave me? To me the latter seems very generic and I feel my department chair could say more about my dedication to mathematics and teaching.