I've owned several thermometers for my aquarium. The first thermometer I had was the hagen floating w/ suction cup. I was trying to clean my aquarium one day and as I was trying to remove it, it shattered between my fingers. I immediately removed the broken glass w/ tiny metal balls. What a pain the butt!! I went out and picked up a plastic Marina/Hagen thermometer w/ suction cup. After a few month, the thermometer in the middle came off the plastic. It was basically held in with white glue. I tried using elmer's glue(non-toxic) and it didnt hold well. I got fed up and looked around for a new thermometer. I really wanted to get the Big Digital Temp Alert on drfostersmith.com, but it was $35($25. on ebay). I was at my
local wal.mart today walking around and I found a Acurite Digital thermometer for only $8.88, it had in/out readings with a temp probe. I came home and set everything up and it worked like a charm. I found it very convenient with the reading of the room temp, which matched my thermostat and the out(aquarium) temp. I thought it was a deal and wanted to share it with you.

Hagen floating w/suction cup


Plastic Marina/Hagen thermometer w/suction cup


Big Digital Temp Alert


Acurite Digital Thermometer


temp probe

I use the smalll digital from Coralife. You can find them usually for under 10.00. I keep the display under the stand so its not visible and cluttering the tank