Frank is right..you need something between the power and the heat source.
However because you are fairly new please (strongly) consider using a cheap thermostat rather than a dimmer. HydoFarm makes a single prob Therm for around $30.
Amazon:
http://www.amazon.com/Hydrofarm-MTPR.../dp/B000NZZG3S
You and your animal will be happier and if you have any "setting issues" a cheap digital Stat will make life....allot....easier.
I wanted to ask about the relative humidity where you are? (State?) The tub should hold RH% well, if you are someplace like Arizona you might have challenges. (we might need to here from someone in the south) Also, we are going to need a digital humidity gauge in there. A cheap one will be fine but please dont get the $5 coil spring type as they are typically junk.
Also, ask for a pic of where your animal is housed now. Sometimes when you move babies they can get stressed out in a bigger tub and stop eating.
Many breeders use small "shoe box" sized Steralite tubs for babies when hatched. If you go directly to the 16qt and your animal doesn't eat...please don't try again in 3 days, or the next day. If the meal is rejected, try again in 6 or 7 days. (once a week). Hoping you have no issue but if you do start to get worried please come here, tell everyone and ask for advise.
(Pictures Please)