As someone who has done a fish in, an ammonia based, and a fish food cycle (or at least attempted to).... I would highly recommend avoiding the fish food cycle. To sum up my experience - Mold, mold, and more mold. Mold that spread like crazy.
Ammonia took a sheer eternity to show up, and there was never any sign that the tank was actually cycling. The filter got clogged by the dissolved food, so I would have had to clean it (and do at least a mini re-cycle) if the cycle had ever happened...
I gave up on it about a month in. The cycle had yet to even start. Ammonia was showing up sporadically, but no nitrites. Just... mold.
I scrubbed everything down, tossed some filter media, gravel, and a decoration in from my "temporary" tank (that had finished a fish in cycle while I was waiting for the real tank), dosed with ammonia, and was cycled in about a week.
Asking around later, I was told to expect a fish food cycle to take three months at the shortest. Ammonia is so much more reliable and easy.
+1 to that. I cycled with fish food a couple of times, and it was hit or miss. Then I was pointed to 'Janitorial Strength Ammonia' at ACE hardware. It works very cleanly and does not leave crud in the water.
I like the idea of just adding ammonia into the tank. I think its easier than the food method. However, I don't recall seeing it at pet stores. Perhaps I just wasn't looking for it?
That is probably because it really isn't a pet supply. I bought mine at a regular hardware store... It was about US$2 for a liter of pure ammonia, which will last forever if I only use it for cycling.
You just have to be very careful that it is pure ammonia with no additives (perfumes, surfactants, etc) If the ingredients aren't listed, better safe than sorry - assume there is some kind of additive and go with one that does have the ingredients (single ingredient - ammonia) listed clearly.
I will vouch for the pure ammonia method and veer anyone away from the fish food method. I figured I'd try the fish food method since I already had extra food I wasn't using, I wouldn't have to buy anything extra. I ended up with a tank full of mold and no ammonia.
Next step was to find some pure ammonia. I don't know if it's just my location or I just wasn't looking in the right stores, but I could only find one or two brands of cleaning ammonia and both had lemon scent in it. Luckily, somone on this site gave me a link to DrTim's Aquatics Ammonium chloride on amazon: http://www.amazon.com/gp/product/B00...ls_o01_s00_i00
This stuff is working great. No guessing or playing around with how much to add. 1 drop per gallon gets the ammonia up to 2ppm. I think I'm on week 4 or 5 on this 10 gallon and my ammonia is going down and my niterItes are spiked and some niterAtes are starting to show. I'm at the top of the hill and I can see the finish line.
I would expect that using pure cleaning ammonia would work just as well once you figure out the right dosage. Good luck!