CatmanDru
Aquarium Advice Freak
...the shop guy said to keep it [the tank] running for two days till I put in fish for the cycle...
Unfortunately, that advice is wrong, but a lot of fish shops say that. I think they must read it from some kind of fish shop or manufacturer literature or information packet. That advice is good for fish store profits, but it's bad or often fatal to fish.
Two bits of wisdom that are often stated in this forum are 1) "Don't believe the fish store", and 2) Do your own research.