160ppm nitrate suggestions?
 

I am taking care of a large ~350 gallon system. Initially the tank did not look good, I found out the top off water was being badly contaminated with copper, and there was copper just sitting in the tank from a brass float valve. Since removing the copper and doing a large (~100G) water change things started to perk back up. Since the fish were showing signs of HLLE and other illnesses I inquired to their feeding situation. They had been feeding frozen food and freshwater flake once a day, and sometimes nothing over the weekend. They also are not currently turning off the return pump for feedings. I told them to feed twice a day, and gave them some algae to feed the tangs. The HLLE on the blue tang looks to be getting slightly better and the white spots on other fishes disappeared but then I noticed the anemones were not as happy as they should plus the nitrates on the dip tests they had went from 20-40ppm. I then decided to try a test with my nitrate kit, which showed 160ppm. I am not shocked at all, other then how poor the dip tests work, since the system has an ancient filter system. Bio balls and filter floss that are never cleaned, no skimmer, no fuge.

My question relates to the fact that I have never had such a a large tank in this situation. What is the cheapest and most effective way to lower the nitrates ASAP? A decent skimmer and carbon dosing schedule comes to mind. But I am also thinking about a macro fuge / ATS in the mean time since the tanks budget is pretty tight, and most of it was just used on a new ATO, controller, filter socks, and food. I will be talking to the building manager on Monday to see what can be done for funding.
Is there anything else that I am not thinking of?
I am also going to be instructing them to go back to one feeding per day until the nitrates are under control.

Any help or suggestions would be appreciated.

I'd look at doing another huge water change for sure, ensuring that all the rocks and substrate get stirred up for the water change (you probably already know this).

Yes adding some fresh carbon would also be a great idea.

Next to that, if there is room to hang a basket or net, get some macro to put in there for a bit of help with the nutrient export (my friends have done this in the past when they had a nutrient spike). You could probably get some macro for free too from another reefer!!!

I am really hesitant to do more large water changes since they are quite costly. I would rather invest in the equipment that will solve the problem permanently.

So far I have identified these issues:
No feeding mode (order controller)
No fuge / ATS (sump needs to be cleared out or marco basket in the main tank)
No skimmer (pending funds)
No filter socks/mechanical filtration(on order)
Flow is too low, 4x 1200gph maxi jets (2x Tunze Turbelle 6085 pending funds)
Light is too dim, 2x 150w 2xPC (2x 400w 4x 48w t5 pending funds)

The question is what will give the greatest bang for the buck as they say.

You should start dosing some carbon source but go slowly. It will take time to lower such huge amount of nitrates, it won't happen in one day. Dosing carbon will be the best way to go I think, for the future at least.

Maybe a reactor with biopellets, but again, go very slowly and a very small quantity to begin with.

A skimmer is a big must in this case.

Can I start a week or so before the skimmer arrives?

I am definitely not an expert but reading about carbon dosing you seem to need the skimmer to export the bacteria that grow in the reactor on the pellets and slough off.

Charles

+1 on carbon dosing but don't start until you have a really good skimmer.

Yes wait until you have a very good skimmer otherwise you run the risk of a major bacteria bloom and a big loss in oxygen, dead fish, dead corals etc. Dosing carbon is something to be done very cautiously, because it can be dangerous if done too quickly and without a skimmer to export all that crap.

nitrate
 

you could build a nitrate reactor out of pvc,black air line and plastic scouring pads-takes about a month for results but it works well

You could try Prodibio? I just recently read on the forum that you don't need a skimmer to use that carbon dosing system.