I used pure ammonia which I added several times (and it didn't stink
) to cycle my tank. Smart start is pretty much just bacteria in a bottle. You don't need to get it though, once again the shrimp will work just fine! Cycling definitely tests your patience. It's really hard to stare at an empty tank for a while
Plus the constant asking from friends or family of "so when are you getting fish?" The filter sock shouldn't be a problem, so don't change it. Might have bacteria in it or something. I didn't use mine during the cycle and everything turned out fine. I have a felt filter sock and it gets dirty quite fast, so I put it in the washing machine once a week or 2 (pre-rinse, then no detergent). It can be a pain, but man does it do a great job at making the tank crystal clear! I read that the mesh socks are easier to clean and don't get clogged really, but aren't quite as good as felt.