New 100 gallon from CL

So, I've been minimally employed for a while now, and as such, I have a lot of time to browse Craigslist. I finally found this awesome deal, $200 and 4 miles from my house. Here are some of the details:

-100gallon acrylic tank, rounded corners, drain on bottom, connects to hose, moderatly scratched, covered in algae and hard water buildup. Full of cool rocks and driftwood, gravel, plants(threw them out, they where yucky). Has a black gravel background, it's pretty cool.

-Stand and Canopy, pickled oak, not my favorite, nor in great condition, but I'm a cabinetmaker, I'll replace it eventually. Canopy has one 48" t12 with room for another, and needs a reflector as well, no biggie.

-Fluval 404, is working great, had a bit of trouble figuring out how to prime it. Also came with a UGF, which I removed, I may add another canister in the future.

-250watt heater, and a couple extras.

-Boxes of assorted accessories, chems, meds, airpumps, tubing, food, just about everything.

LIVESTOCK!!! I was so stoked about the fish, I actually want most of what he has, he said he had about 40 cichlids and two big plecos in his ad.

I found:

-56 Juliodichromis Marleiri (fairly certain about that ID, but correct me if I'm wrong) I was actually really proud of myself because I ID'd them as Julies on sight, and I'm no pro on cichlids. Assorted sizes, from 1" to about 4.5" adults. I lost a few small ones during the move, bummer, 56 is what's left. He says they've been breeding like crazy in there.

- 1 mystery cichlid, haven't figured it out yet, ID it if you can.

-2 Plecos. One 14", one 9". The big one is beautiful, the smaller one looks kinda chewed up, any ideas what caused that? I think they're common plecos, although the big one has really nice patterns on his back and belly, and big pretty fins. I think the large one at least will have to go, ya'all shoulda seen the amount of poop in the tank before we took it down.

I stored them in a cooler overnight with an airstone, then moved the cichlids into a 10 gal (looked like a bad petstore) for a few hours until I got the tank setup in the afternoon.

I think I'll be selling or trading a lot of the Julies and the big pleco, still thinking about keeping the small one for a while at least. Let me know if you're in the SF bay area and you want some, I really don't want to ship.

Here's what I've done so far:

-Moved. The guy I bought it from was so incredibly nice, he spent about 3 hours with me, offered my wife and I beer or soda(I refused, for once), emptying the tank, loading it, and he even followed me to my place to help move it in. Then, he tried to give me 20$ BACK from the original price, I refused and gave him one of my handmade pens.
-CLEANED: scraped the heck out of the algae with a plastic putty knife, vinegar for the hard water deposits, rinsed out the gravel, hosed off the rocks, rinsed, drained, etc...
-Set up, mostly this is temporary, as I'm going to Mexico in a few days. Hooked up the filter, heater, light, put in the gravel, rocks, and driftwood. I'll probably get more rocks and I'm considering either plastic or real plants. It's still getting clearer every time I look at it.

I'm thinking about keeping this as a Tanganyikan tank, and I'd like to add a bit more variety, some color, maybe a school of target fish, and some more appropriate scavengers and algae eaters. Right now there aren't any top or middle level swimmers as the Julies stick to the rocks, and the Plecos to the bottom.

I'd appreciate any suggestions or tips on stocking and setup.

Here's some pictures for now, I think they're pretty self explanitory.

Well, I lost a few last night, I counted 5, hope there aren't any more in the rocks.

Everybody seems pretty subdued this morning. I tested the water,Very hard 400ish, no ammonia, nitrites 0, nitrates 20, pH about 6.8. Darnit, I think it's pH shock. I used distilled white vinegar to clean a lot of the tank, and although I thought I rinsed well enough, I must not have gotten enough of it out, couldn't be more than a tablespoon or two left in the whole tank. How much vinegar would it take to lower the pH that much?

Another possibility is low oxygen, with that many fish in the tank and only the output of the filter to stir things up. It's well under the surface though, and not causing much aggitation, it does create a good amount of current in the tank though. I added a couple airstones with a pretty strong pump, that got the surface rippling. Some of them seem to be perking up now, maybe the light coming on had scared them. The big Pleco keeps taking gulps at the surface, first he lets out a cloud of bubbles, then up to the surface and CHUG. I must admit I'm a little bit scared of him.

So, should I try to do something about the pH, or just let them adjust to it and gradually up it with WC? My tap is about 7.8. Could use some crushed coral as well, if I can get in a trip to the petstore tonight.

Here are some new pics, and a good one of the mystery cichlid, I think he's a malawian.