I am really getting in a mood tonight on these threads. Would somebody please make a trip to this LFS, grab said employee by the ear lobe, drag them to the nearest public aquarium, and throw them in with the sharks.
Lets see how to put this politely....
The LFS employee you were talking to is a total idiot who has almost no knowledge whatsoever about saltwater fish or filtration systems. Not only is the mandarin a sure bet to quickly die in a 10 gallon aquarium, the addition of a hang on filter will do nothing to help the cause, other than put a few extra bucks in the cash register.
Wow. This really has my blood boiling. Are we allowed to post names and phone numbers of LFS? I'd like to make a phone call.