They key is not to add anything without being able to test it.
trust this advice. the salt you use to make your water, along with quality water to start will give you most of what you need. i have noticed that with adding more snails in the past week my tank is running a little low on the calcium, so i plan to add calcium occasionally, only because i can test for it and monitor what the impact on the tank's params.
i have just upgraded to a 55g, i currently plan to do 5g water change weekly, 10g every 3 weeks. you'll have to figure out what is right for your tank. as long as everything is looking happy & healthy, you're on the right track.
oh yeah, and ask for advice before you do anything, there are so many helpful, experienced people on TRT, I owe my tank's health to everyone who contributes on this forum...