it just dawned on me reading this that i left out 2 other places ...
they are both saltwater, but both sell a lot of used equipment (and at times VERY VERY cheap)
one is called "Phishy Business" and its in the gahanna (east columbus) area. its on hamilton road, just south of morse rd. in a strip mall. (oddly enough its 2 doors down from a sushi place

). anyhow, they have a small/medium selection of SW fish, but at reasonable prices, and a decent amount of coral / rocks for SW. but the used equipment is worth sorting through IMO if you are looking for something and in the area. i dont go there often, but it seems like they work bankers hours! so i would call before you go too far out of your way.
and the other place is the New Albany Reef Systems. its a little out of the way, but if your into SW this place is AWESOME, and you should check it out! he has a ton of stuff set up. i think he said he had more live rock in his place than all the other columbus stores combined?
he has little or no fish for sale, but he has some in his displays. he is very very nice to talk to, and from what SW people tell me, his prices are very good. last time i was there he was still cycling his 900g display tank, but i'm sure that will be a sight to see once completed. he also has a big kio pond in front of his house thats pretty cool. its only open friday, saturday, and sunday b/c he works another job.
and i think when i have emailed him in the past he usually does a good job getting back to me with any questions.
check out
www.reefsystems.com for more info
and if you have some extra weekend time, go check it out!