what are your thoughts on using tapwater in a reef system? anybody ever used the tapwater purifier by aquarium phamaceuticals? i'm currently using tapwater in my nano-reef. big mistake?? everything seems to be doing fine. i've had my bubble coral for almost 2 months now and it seems to be doing great. anyways i think i've decided to purify my tapwater. but i'm on an extremely tight budget. is the tapwater purifier okay? or are there any decent R/O D/I units for a good price??