[RAVEN]

Cindy, I can,t tell you exactly why the digital won's are unreliable, but the fact that most of the retailers that used to carry them said they had lots of returns on them due to problems. I have heard that the digital readouts are inaccurate many times and that they tend to overheat your tank. I only use 1 heater in my tank but I have one of those digital thermometers that has a high and low temp alarm, they are well worth the $30. The temp in my tank never varies 0.5F. I also have a back up heater if the main 1 fails but I dont keep it in the tank. Already have too many damn powercords as it is. If you go with 1 heater I would get the 350w won, but 2 heaters are probably better. Of course there is always the problem of 1 heater breaking and over heating the tank. Thats the risk with any heater and you are doubling your chances of that happening.