It could be a bacterial bloom, depends on what color it is. Bacterial blooms are white. They're harmless, themselves, but usually a sign of bad things happening (at least in terms of having fish in there), like ammonia. Depending on where you live, there could be ammonia in the tap water, or chloramine which often leaves ammonia behind when you use water conditioner. Since there's no fish, it's safe to wait the bloom out. Green water is algae, which can be caused by excess sunlight, among other things. Brown clouding can be tannins from new bogwood. It's also harmless, and will go away over time.
The water conditioner is fine, but Cycle is junk. There's a handful of brands that can potentially work, but most of them still don't work nearly as well as advertised, and even the best aren't always reliable.
You're right with the filter media. Generally speaking, carbon isn't required, but it won't hurt. It will be depleted within a few days, however, not the month the filter documentation probably says. The polyester is probably the biological media, which will eventually be home to a large colony of bacteria which will nitrogenous waste products in the water.
Leaving the tank run for any amount of time, however, accomplishes nothing. Going on shop advice, you're no more likely to escape the terrors of New Tank Syndrome bringing fish home with the tank than you are leaving it run even a month. You'll want to cycle the tank, which requires a source of ammonia. Please review this thread, since you're fortunate to have found this site before you got your fish. It will take some time, 3-5 weeks is typical, but it's far less work than trying to keep fish alive through the cycle, which will require large daily (sometimes twice daily) water changes and potentially take longer.
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/www.fishforums.net/content/New-to-t...shless-Cycling/"]http
/www.fishforums.net/content/New-to-t...shless-Cycling/[/URL]
Edit: Last edit broke the link formatting