[Scuba Kid]

lmao. Sorry to disappoint.

I'd agree with all of the above, but to add one more thing, I believe the pre-mixed water has much less trace elements than most salts which are very necessary in most tanks and especially with corals. Of course, you can add supplements but if you're not keeping corals, that's not necessary with a good salt mix. Plus, its just easier to start out with a good salt mix, which is usually cheaper than the crappy pre-mixed stuff anyway. And it lasts longer.