Forget about pH, with hypo it will never be 8.2 no matter how much buffer you shovel in there, I have QT'd over 30 fish, and have yet to check pH in a QT. You will want to get yourself a new Ammonia Test Kit....you'll use the hell out of that guy. Some people will measure Nitrite, but again, with SW it's not nearly as toxic as it is with FW, I only measure it simply to tell me where in the cycle I am.
As for the saltwater, tap water with a conditioner such as Prime is just fine also. I just take a 5 Gal bucket to the bathtub, fill it up, mix some salt in, and do the water change an hour later. Amquel works equally as well, however a bottle of Prime lasts much longer. Per the manufacturers directions, 5 mL of Prime is good for 50 Gallons of water, 5 mL of Amquel is only good for 10 or 20 Gals. That same bottle of Prime or Amquel will come in handy later when you start dealing with Ammonia, and can't immediately do a water change.
If you're starting to loose fish now, you want them in QT as quickly as possible, so once the water is mixed and up to temp, start transferring them over. You can use Carbon, or even a carbon w/ ammonia binder in it, but it will be depleted quickly, so be ready to replace it every couple of days.