I have my own equipment for a salt water setup now. A friend of mine has had his tank for years and he's loved it but he just can't keep up with it anymore. He loves the tank but it's become more of a chore than a hobby. He knew I kept fish and when he asked I lept at the chance to get a salt water set up. He gave me everything. A fish, liverock, and every bit of equipment he had. The fish were in fantastic condition but had to go back. The liverock was similar. I just don't have the capability right now to keep the live rock live for the amount of time its going to take for me to get this thing set back up. The LFS did give me some store credit though.
There are a few issues, not the least of which is that the tank isn't a 90 gallon, it's a loathed 55 gallon. That gave me pause and for a moment I actually debated saying no thanks to the set up. After all, everything I've had to say about my 55 gallon fresh water setup has been in the vein of "I will never buy another 55 gallon tank in my life." I got this one for free though so I guess I'm not a total hypocrit.
The other issue, the big killer, is that the stand is shot. I know why they build then out of particle board but the idea of setting 700 pounds of water and rock on top of particle board... ugh. To top it off this thing has been running for 8 years. The stand is just gone. I barely trust it to hold the tank right now while it's empty. Also, several fittings got broke in the take down. You see he didn't set this thing up himself, he paid a LFS, my LFS of choice actually, to come in and set the tank up for him. Well the chuckleheads didn't use unions, heck they didn't even use threaded fittings, they glued everything. Combine that with a stand with crappy access so you can't get any cutters in there to start cutting pipe and you've got a problem. I broke the return bulkhead and a fitting on the UV sterilizer both of which will need to be fixed. I guess I can throw the rest of the plumbing in here to as part of the "need's fixing" since I can't reuse any of it.
For the moment I'm not planning on a reef tank. I'd like to not exclude the possibility of eventually doing one by virtue of equipment selection or set up but for the moment I'd just like to get a FOWLR set up going.
So, on to what I've got.
First up, the sump.


This sucker is straight out of the LFS. I can actually go in and lay hands on a pristine new one of these right now. The big problem here is that inlet filter sock. Never cleaned once in 8 years. Did I mention that the LFS guys didn't bother to tell him how to maintain what they set up? They shot themselves in the foot on that one as my friend was a heck of a conscientious fish keeper and would have gladly done what was needed to keep the tank in good condition. My only plan with this is to yank that inlet sock out and clean it.
Next up, and this is a big one with me, the RO system.

So I save about $200 because this system is a 100gpd. The downside is that I'm pretty sure I need to replace all the cartridges and membranes in it. 8 Years and I'm pretty sure no maintenance.
The light.

All the identifying marks on this thing are gone. I'm sure the bulbs are shot as well. Anyone got any idea what make and model it is?
Skimmer

Again, 8 years in the sump have wiped out any identifying marks on the skimmer itself. Any idea what make model it is?
UV Sterilizer

It's a big sucker plumbed into a recirc line. It clipped into a fitting on top of the sump. Unfortunately that led to this:

Hard pipe, crappy access, and I probably didn't take as much care as I should have. Oops. I need to find out if this is terminal or if I can get a replacement part to fix it.
Return Pump

Model 9.5B is ringing a bell but at the moment nothing springs to mind. I'll be going through Fosters and Smith as well as the LFS for some clue as to what all this gear is specifically but I don't mind help here either. Oh, this is the sole union fitting in the whole set up. The only connection that was taken down without a reciprocating saw or pipe cutters.
Heater

I'm leaning strongly towards just tossing this one and buying a new one.
Tank

Ah the tank itself. It's gonna need a righteous scrubbing.

Already plumbed. Though with all the intake and return in one corner of the tank it's doing nothing for a 55's naturally crappy flow. I'm considering removing the locline parts and extending the return to the other end of the tank and trying to establish some lengthwise flow with it. Not sure how I'll secure the horizontal extension but one step at a time.

The stand itself is just half rotted away.

And here's the bulkhead I managed to snap off

Go me.
Anyways, that's what I've got. Its in my hot little hands now and I'm itching to get moving on it. So my plan for the moment is this:
1) Build a new stand. Until I have somewhere to put it anything I do with the rest of it is pointless. I'm going to be building it in my grandfather's shop (owner of every tool under the sun, including a drill press that can drill a square hole) with his assistance. I've got some basic ideas for it already though I do have some questions. Primarily do you build it out of any kind of moisture resistant wood?
2) The sump. I've already got one right so what's the problem. Well, I've got a 55 gallon, non-drilled tank sitting at home that I haven't been able to unload. My maniac impulses have me looking at that thing and thinking SUMP. I'd have to get some acrylic and a clue what to do with it but it's 55 gallons, sturdy, and glass. I could wind up with a 100+ gallon set up quite easily by using this as a sump. The only real downsides are water changes get bigger for a given percentage changed (an issue with having to purchase salt. I'm not trying to cheap things I just can't be frivolous with my money) and the shear physical challenge of getting that monster in the stand. This is mostly just a decision point not so much action.
3) Clean it all. Everything needs a good scrubbing before I start over.
4) Repair the busted bulkhead and look into getting the sterilizer fixed.
After that's all done we'll see how it goes.