Hydor Theo Aquarium Heater

“I have been using a Hydor Theo without any problems for the last few years, though it is ran by an Aqua Jr. Controller and temp probe.”

“I am trying to find a heater that is better than my Hydor Theo 50w, as I am not that happy with it. It heats the water, but the temperature is not as stable as I would like.”

“I have a Hydor Theo for my water changes water (~2.5 gal bucket), works great. I had to play a little with the control to set the temperature where I wanted but after I got it right, I had no problems with it.”

“I tried to replace it with a hydor theo, which was supposed to have an auto shut off, but it cooked my tank to about 90*. I put my old visi therm back in and it works good.”

“I've got a 100W Hydor Theo in my 29g tank that's about 18" from the 20H and it doesn't have a problem keeping the tank warm.”

“I use hydor Theo no complaints at all.”

“I tenaciously discourage using Theo Hydor heaters, to many horror stories tied to them specifically, them overheating the tank to 90F, there is also a recall associated with these heaters as well.”

“Hydor Theo heaters have a bad reputation for maintaining temperature, and they often run hot. That has been my experience with them as well.”

“replacing my Hydor Theo, which is wildly inconsistent, with the Cobalt Neotherm 50w”

“I currently have a hydor theo in the tank and its very unstable.”