Calcium and alkalinity

I'm really confused with calcium and alkilinity... I'm goi g to have a pair of clown fish in my nano aquarium, is calcium and alkilinity important if I don't have corals...? I'm going to add corals once my tank has reached 1 year, will it affect the fish if there is too little or too high?

bang guy

Yeah, unfortunately it's still important if you want to keep your Clownfish healthy. In small systems it's easy to maintain good levels just doing water changes. Another good thing with a fish only system is the Alkalinity and Calcium will be consumed much slower compared to a reef system.