for a brb you arent going to want very high temps anyway (under 90 degrees at the animals level), so any of the above mentioned heat elements would suffice,
when attached to a thermostat as smy said
With BRBs, humidity is a high concern. You may want to think about an UTH with thermostat; use a temp probe (or better yet, a temp gun) to measure the temperature that the UTH is producing at the top of the substrate as well as below.
I would be cautious of red lights since you will be trying to keep humidity up; but that being said that is what i use for 50% of my cages (i keep colubrids though). Both CHEs and red lights can dry out the tank; but if you are misting frequently they may work. my medium CHE (cant remember wattage, sorry) heats up to ~600 F at the bulb, and 18 inches away is roughly 90 degrees. Even on a dimmer, this may be insufficient for your acrylic tank and could melt it.
I would go with UTH or heat tape (or RHP? dont know much about those) in your case, but the KEY here is that you MUST have a thermostat as well.
LOL SMY, my computer keeps autocorrecting you to 'amy', sorry