I don't see you posting any parameters of your tank, did you buy test kits? Stop buying corals, and stop buying fish, until you know exactly what your tank levels are.
Also, your tank is too small for 3 fish. I'm guessing somewhere around 30L water volume.
To repeat, you need to stop adding things until you can properly care for what you already have. Throwing more into a tank when corals are dying is a sure fire way to kill more corals.
sadly not.. i was curious to put one different type of coral to see what will happen if the temp is 26-27 degrees
now i'll stop buying and save money to buy kits..
not too small for me.. atleast I have 3 small fish..
okay, I'll stop adding things now..