Agree here with what was said about draining and restarting. With that high of a copper content, not only will you see staining on surfaces, you will also stain clothing and blonde hair will turn green. The only way to get rid of the copper is to replace the water. However, if you truly wanted to "wait", you can spend a fortune on a sequestrant that will "suspend" the copper preventing it from attaching to surfaces. However, this method will cost you a ton of money in the long run as you'll have to constantly be adding the sequestrant. I believe the Pristine system sells the "PrestineClear", which is their sequestrant to "prevent staining". Pristine is an entire "system" that you must continue to follow in a mouse wheel (round and round) spending more and more money to constantly fight the damages caused by the previous item.
Are you like most that have been using the Pristine system and not adding any other type of sanitizer except the "shock" you're adding weekly? I believe the Pristine system calls it "PristineXtra", which is 99% sodium di-chlor (granular chlorine). Did you add any stabilizer (CYA - cyanuric acid)? If not, then the chlorine within your "shock" is likely burning off within a couple days, leaving your pool completely open to bacteria until you shock again.
Needless to say, Pristine is a terrible. The TFP method is 100% the way to go. I get the 10% sodium hypochlorite 1gal jugs from Walmart for like $5 or $6. I go through one to two a week (usually about a 1/4 a day) during the hottest days of the summer. 28k gallons, you'll probably go through closer to a gallon a day during the hottest part. But still, far cheaper than the Pristine system and far less damaging, not to mention safer.
Get you a TF-100 with smart stir. Or opt for the TF-Pro at tftestkits.net. This is an absolute must. The test performed at the local pool store are a joke. They are usually wrong, especially on CYA and other tests. I've found ours to be somewhat "close" on FC, CC and pH, but that's all they are good for. Then they try to sell you a thousand things. Those tests are there for them to sell you stuff. Strips aren't as accurate. Neither are the cheap droplet tests you buy at a local store. Get the quality one from TFTestKits.net.
#1 will be some sort of sanitizer, recommend just straight liquid bleach (like I mentioned at Walmart). Your TriChlor was adding CYA, which you don't want to get too high either. If it gets too high, then you have to add way too much chlorine to be effective. The only way to lower CYA is drain some and refill. Or just wait for it to naturally evolve through natural water replacement (backflush, vacuum to waste, etc.) CYA DOES NOT evaporate. So once your CYA is too high, you'll have to drain and fill. Relationship between CYA and FC (free chlorine) explained here:
Free Chlorine and Cyanuric Acid Relationship Explained
Pool School - Pool School - Great to start here.
Recommended Pool Chemicals - Recommended Pool Chemicals
The only things I keep on hand really are 10% sodium hypochlorite (bleach / chlorine, used to sanitize), Chlorine Stabilizer (CYA, used to keep a "reserve" of chlorine from being eaten by UV), Muriatic Acid (buy it at hardware stores.. usually sold as a "concrete etch" or wash, used to lower pH), and calcium chloride (I have to get my calcium levels up usually once a year as mine can fall below 100 for some reason).
Hope this helps. Until you have that test kit, there really isn't much we can tell you as for what chemicals you will need.
