Also, I have a TBI so if you could simply dumb it down for me haha.
I'm sorry to hear that. My wife was a social worker for many years, and has a personal interest in helping those with TBI's.
I'm not an expert with fish diseases,
@vetteguy53081 is one of R2R's experts, so please follow his advice.
But in an effort to help, yes, you will need to setup a QT tank.
You can quick cycle your QT tank using some bio media that's not rock (think plastic bio balls or I believe ceramic media is OK (real rock reacts with the medications you'll be using)) from your main tank, if available.
You can try a fast-cycle bottled bacteria product like Fritz Turbo Start:
https://www.bulkreefsupply.com/fritz-turbostart-900-algae-barn.html?ab_version=A&utm_term=&utm_campaign=EL+|+ACQ_Prospecting_PMax+|+ROAS+|+Open+Targets+|+Low+Margin&utm_source=google&utm_medium=cpc&hsa_acc=7373341438&hsa_cam=17740353356&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gclid=CjwKCAjwjsi4BhB5EiwAFAL0YInYRW5ho_7Ql0_-h5YwMaOzyihccikBzooipzmjxAjVXYAhqap6YxoCIOIQAvD_BwE
You can monitor your ammonia, and do water changes as needed. In addition to a decent, non API brand ammonia test kit, you may want to try putting a SeaChem Ammonia Alert badge in your tank:
https://www.bulkreefsupply.com/ammonia-alert-continuous-ammonia-sensor-seachem.html?ab_version=B&utm_term=&utm_campaign=EL+|+ACQ_Prospecting_PMax+|+ROAS+|+Open+Targets+|+Low+Margin&utm_source=google&utm_medium=cpc&hsa_acc=7373341438&hsa_cam=17740353356&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gclid=CjwKCAjwjsi4BhB5EiwAFAL0YHOOtbUhcGpD7frja8y7Sc7POV7aDeLsdvPWqb-FWYOZIvfOk7e_3RoCVz8QAvD_BwE
Your bacteria will need some media to grow on, but don't use rock or sand in your QT tank. Use a bubbling sponge filter or a Hang On Back (HOB) filter with plastic bio balls or something like that. An extra air stone going in the QT tank isn't a bad idea either.
Outside of any ammonia concerns, you can do a water change as needed, but keep in mind this is a temporary QT fish-only tank, and, in my opinion, doesn't need typical weekly water changes. Your fish won't really mind if your nitrates go sky high, so you may not need to do many water changes at all, except to potentially manage your ammonia situation.
The deal with the water changes is just that, when you dose your QT tank with the correct level of copper (2.25ppm), you need to consistently maintain that level. If the copper level drops bellow that concentration, you need to basically restart your copper treatment like you're on day 1 again. When you do a water change, you don't want to remove water from the tank and then add back untreated saltwater, causing the concentration of copper to drop bellow the therapeutic concentration (2.25ppm).
So if you need to do a water change, simply dose the water change water up to the therapeutic level (2.25ppm) before adding it to the tank. That way, the concentration of copper in your QT will not drop bellow the recommended concentration. I hope that answered your question, let me know if you need further clarification here.
And to measure your copper, I think almost everyone here uses the Hanna copper Checker. I don't even know if there are other test kits available for copper. I'm assuming you're not going to have a Hanna copper Checker, but I'd recommend that you look into getting one. In the meantime, just in my experience using the CopperPower product, if you add it following the directions (I think it's 1 ounce to 20 gallons), you'll come out right about in the range you want for your copper concentration. But best practice BY FAR is to use a test kit to be sure.
https://www.hannainst.com/hi702-cop...S9VU1svVJHmWu9gNiyGugqmOuubJe2MhoCP-oQAvD_BwE
And the CopperPower medication:
https://www.bulkreefsupply.com/copper-power-parasite-treatment-endich.html?ab_version=B&utm_term=&utm_campaign=EL+|+ACQ_Prospecting_PMax+|+ROAS+|+Open+Targets+|+Medium+Margin&utm_source=google&utm_medium=cpc&hsa_acc=7373341438&hsa_cam=17740353356&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gclid=CjwKCAjwjsi4BhB5EiwAFAL0YI9hg5uERwkWK2FRYCS0eCuNb9kjrjeVJj4DZnIFYN5VUOd-jlf1zRoCMd0QAvD_BwE
I hope that helps! You're in a tough spot for sure, and I wish you the best of luck!