Celtic - I believe there are two different types of humidifiers. I cant remember what they are all I know is that one of them harbours more bacteria than the other and can cause more harm than good in littlies. Sorry I cant be any more help but I am sure I read the info on this site. I got one for C when she was all blocked up and it works great - water in it lasts 10 hours so that does her all night. Mine only cost $80 so I was happy about that. I dont use it now cause her nose/chest is really good.
Good luck!