sounds good dude. How old is the tank? its a 28 day cycle for a tank to produce a culture of ammonia eatting bacteria, so my advice to you is go snag 2 zebra danios for about 2 bucks and slap them in your tank to continue the cycle as the bacteria need ammonia (fish waste) to feed off, so by having no fish in there you will have to start your cycle over again perhaps. Your shrimp and snail most likely wont make it through the cycle, as they are pretty sensitive to ammonia and no3 and no4 which are natural to your tanks culture process. Typically you wil want to establish a tank for prob around 2 months prior to cardinal tetras as they dont like variance in water quality. I suggest to you to get some peat moss and cut your filter sponge in half and drop that bitch into the back of your filter ( assuming an aquaclear) Bag the peat in a panty hose so it doesnt get all mucky in your tank. Get a piece of real driftwood aswell, both peat and driftwood will soften your water and do wonders for plants, and the type of fish youre looking at. If you have lighting on the tank, it has to be tube lights... not lightbulbs for plants. You can start adding hardy plants after day 28, some plants are impossible to kill and greatly help control algae like mentioned before. Dont listen to pinheads at the fish store, if you have questions just let me know and ill lead you down the path to a good, easy to maintain fish tank.
also, return those danios when they finish the cycle... they are not very cool fish and can be really pushy.