Hey popss,
I've read many of your replies over at OscarFish.com. Anyways, the tank has been running since July, 2012 so in this case we're way past the need to discuss cycling a new tank. Thanks though. That info echoed many of the comments I got from the guys here at MFK and from the guys on the OFish forums (you know who I mean).
I've been using Prime since day one and will continue to use it. I recommend it to all my fishkeeping friends. As you have suggested, I do dose for the entire water volume of the tank at each water change (and don't fire up the filters again until the Prime has been added). Water changes average about 50% of the 155gl volume each time. Though I have done a 70% WC on occasion.
I also agree with your other suggestion, the API Master Test Kit (Freshwater). I bought one of those prior to the setup of the tank. I recommend this to others also. Good stuff.