I don't know...I guess people who know a lot about about herps and reptiles and that choose to work in the field usually work in more specialized and advanced areas...not pet stores. You will occasionally find someone who works in a pet store who knows what they are talking about...but it is rare. To begin with, most pet stores don't carry a lot of garters. My local pet store, where I often go to get bedding and little hides and such...everytime I go in there the guy that "manages" the reptile department asks me how my corn snakes are doing... Anyway, red bulbs or black bulbs will be fine...if you go with black just make sure they are black light and not blue...some blue bulbs have UV in them. You want to look for night bulbs that do not contain UV. If you are unsure at all...just go with a red night bulb. 40 or 50 watt is good. You can put a pic up of the bulb packaging when you buy it and I make sure it is the right kind. If you want to buy it online...I could give you a link on amazon. It will be cheaper there than in the pet store anyway.

http://www.amazon.com/Zoo-Med-Nightl...490646&sr=1-96

http://www.amazon.com/Zoo-Med-Nightl...90885&sr=1-290

http://www.amazon.com/gp/product/B00...pplies&sr=1-10

60 watt seems to be the lowest wattage in the black light. You can just print pics of these out and take them with you to the store if you don't want to buy them online.