If you're going to cycle, I wouldn't stress too much about your water parameters before putting in the rock. The cycle is going to cause them all to go nuts, so don't worry too much.
Those filters you're referring to aren't going to be a big help. They're basically just charcoal filters. While they do remove some stuff and make the water taste good, it's not going to pull out the stuff that will cause you issues in a reef aquarium. Like Thom said, there's a lot more stuff in there.
system really is your best bet. It's a little pricey upfront to get the gear, but it will be well worth it to save you the algae issues you'll likely have (YMMV) without it. A decent unit can be bought on ebay for around $100, and it really is a sound investment.
Not to say you can't be successful without one, because you can, there's just a lot more risk of things getting nasty in the tank.