After following this thread I have decided to setup a 10-gal. QT too. When I look at what I've spent in equipment it really seems irrational to not spend $100 more to start it off on the best foot possible.
I have a question about QTing a couple of clown fish while my new main tank is cycling. If I filled the QT with LFS water to quarantine the fish can I then just add them after my main tank is ready? I have a RO/DI coming from BRS too, but I assume I couldn't use the fresh RO/DI saltwater in the QT since it hasn't been cycled?
typically if using an uncycled QT your best options to manage the chemical nasties like ammonia and nitrate are:
1. careful monitoring and large, regular water changes. like LARGE water changes, as much as possible, and done every couple days, or as needed based on your testing.
2. using ammonia locking products like amquel coupled with LARGE, regular water changes. things like amquel will often skew your test results for ammonia, so testing can be unhelpful here.
something like Tank Transfer Method, aka TTM, relies on this sort of principle. you're setting up and taking down a small tank every 2 - 3 days, using new water. so ammonia doesn't have a chance to built up.
as tmz stated, don't use waste water from other sources except your own disease free display tank. it would defeat the purpose if you used old water from your LFS.
the bacteria that provide the nitrogen cycle are mainly benthic. meaning they dwell on surfaces, not in the water column. there may be small amounts of them floating around at any given time, but not in significant numbers to have any appreciable impact on the cycle. this is why we use "live rock" and not "live water" in our tanks.