Crowd-sourcing legal advice from non-lawyers is rarely advantageous. I was surprised at the conclusion reached by Nathan that you'd owe interest on a deposit if you held it more than 6 months. Then I went to the NOLO link, and was even more surprised to see how bad their summary of Ohio law is regarding security deposits. I'm not sure I want to even check on how bad it may be regarding anything else.
I'm obviously biased towards retaining a professional to help you in matters like this because it is how I make my livelihood. Note that I said livelihood, as in, I follow developments in landlord/tenant law for a living. You can read the statutes yourself (you linked to the applicable one here) and you can read guidance as it comes out from HUD, etc. You can probably do this while juggling another job if you are so inclined. But even if you do these things, you are going to miss out on a huge chunk of the law in court decisions applying the statutes. These are not as readily available as the statutes (searchable databases require subscription fees) and require some expertise to efficiently find applicable decisions. I would suggest that you should learn the basics, and I can tell you are trying to do so through your original question, but I'd consider linking up with someone who deals with exactly these sort of issues for a living. It isn't going to cost you an arm and a leg (just a finger or two) and you'll probably end up saving money by not following bad legal advice from strangers.