lol nope cmor they're still sold.
but anyway it may very well be that because it gets cooler at night the heater has a hard time heating since its not too strong of a heater, just do like he did and adjust until you get the right temp, heaters are known to do all sorts of funny things somtimes.
look for a HOB
(hang on back) filter, Aquaclear is a good brand, maybe an AC30 or AC50 ( usually cut the filter rating in half, and anyway overfiltering is almost never a bad thing!) and you want the heater to be near waterflow so the warmer water gets around the tank