Basic additives for a 20 gallon nano?

Just want some expert advice on what types of supplements I should be using for my 20 gallon tank. I have had it for a year and a bit now and haven't bothered with any supplements yet. What are some basic supplements I should be using and how often should I use them?

My tank has mixed corals, and anemone, inverts, and two clowns.

 

I would say that a 10% water change weekly would be more than you need to keep levels up in a mixed reef nano.

 

agreed ^ i tried supplementing my 20 gal awhile back and it just made it more unstable. if you use a quality salt meant for coral growth then you will be golden. Just be sure to keep yourself on a routine and use ro/di water. Also an ato is one of the best investments for a nano tank. made my life so much easier. The only i thing dose on my 20 is seachem reef trace and reef plus.