So what you need to do first is learn how to test
Then how to keep parameters stable..
Based off the information posted so far you are NOT ready for any corals..
Your alkalinity could be 3.8 though.. Are you reporting it as dKH or meq/l?
Its fine if meq/L and WAY low if dKH..
But yes your cal is low and mag is WAY low..
What salt mix are you using? Something is not right there..
Did the LFS test your other parameters? if so did they say anything about them being so far out of whack?
Read this to start also..
http://www.reefkeeping.com/issues/2004-05/rhf/index.php
Also.. Its very likely that dosing will not be in your future.. So don't get sold on that stuff.
Your water changes along should keep everything in check..
But something is really wrong with your important alk/mag/cal... So lets get that all squared away first... Lets make sure we are starting with correct numbers..