first off, i would like to welcome you to RP, secondly, out of curiosity, how much is the conversion for baht to peso?
how long you did you prepare your tank water before putting in corals? i believe you need to wait for at least a few days for the saltmix water to stabilized before actually adding it into the tank, and if you are going to use it for a coral tank, i think you need to allow your tank water to mature before putting in corals, not unless your using NSW,
and by looking at how clean your tank is, (no signs of algae bloom, etc) i think you need to let your tank mature a little bit more before adding in any corals,
the parameter swings could also contribute to the fast dying of your corals. i suggest you setup your nano tank properly to ensure that you livestocks would survive as well as not waste any more money..
HTH!
-stan