just get regular low voltage bulb to provide night/day cycle, anything would do including regular table lamp

I usually use 13W energy saving bulbs for mine, unless it is a very big tank ( not for pacs). you sure don't need anything with a dimmer for lights, you need those for heating lamps.
for worms- never feed your pac anything from the outside, it may not contain pesticides, but may have heavy metals and who knows what.