[addict]

I dose Seachem Reef Complete whenever the calcium levels drop below 450, which also replenishes some Magnesium and Strontium.
I also add a half-dose of Kent Iodine whenever I think about it, and I use some Seachem pH buffer if the pH ever gets out of whack (which thankfully it hasn't since about the second month running).
Other than that, all trace elements and such are handled by water changes... normally a 20% change once a month...