appreciate ur sincere concerns nutx, dun worry, i noe the basic rules of the game. i introduced the sps/rics slowly. 1 by 1. moreover, i buy some, i oso sell some. hv monitored my parameters closely. currently, NO3 is at abt 20 to 30ppm using salifert, kh is abt 9dkh, ph is abt 8.2, calcium is at abt 440ppm to 460 ppm. i m oso doing water change once every 2 to 3 wks.