HydorTHEO 50 W Aquarium Turtle Tank Heater, Submersible, Anti-Thermal Shock, Shatterproof, with Graduated Scale and Suction Cups

So I bought this 50 w heater for a 25 litre aquarium, firstly the dial on the heater was a good few degrees off what the temperature of the water was (I verified with two other thermometers), secondly I went and bought a power usage meter which records the daily KWh usage, this heater was using about 0.60 KWh per day, I thought that was quite a lot so I switched to my spare heater also 50w (Eheim Jager model) and now im using half the electricity!! im no aquarium heater expert but I believe this heater is just not as efficient as one of the coil models.

Fitted in my small aquarium great but over heats. Have used a strip thermometer and now a digital one to get a more positive reading but it’s set at 22 and the tank is consistently at 30? Not doing what it said it would so disappointed especially after so many good reviews on various different webpages too.So turned it off over the summer as tank was ok temp wise without it. As the weather has cooled this weekNoticed the table was heading towards 20 so popped the heater on. Again, the heater was set at its lowest temp, pointed in the arrow indicator, so less than 22 degrees and again it has taken the tank to 30 degrees. Not very happy and not very happy fish either.

This was recommended as the best nano heater around however, I have to set at 4 degrees lower than i want. I set it at 26 the next morning the water was 30, checked with various thermometers but now have it set at 22 to get 26 degrees. Dissapointed with that.

fab little heater. 7 inches long and quite slim. the control knob makes a nice clunk when turned and moves smoothly. keeps a 5 gall tank at a steady temperature that matches the setting reasonably. the best nano heater i've ever had. would totally recommend.

In my opion, these are the best tank heater out there,, shatterproof and they last a long long time compared to other heaters,, odour all the way for me

At the moment it is working perfectly and there has been nothing wrong. There are alot of reviews on here with people having problems I have yet to have one but if I do I will let you know

This is one of the few times I've felt compelled to write a review. While the heater is a good size for a small tank at a reasonable price. It is completely inaccurate, to the point where I have bought a second thermometer to double check. It runs 4-5 degrees hotter than temperature selected on the thermostat.

This is the second one we have bought of these,it's great for a nano tank. Even though I chose free delivery it arrived in two days. The first one we bought has kept the temperature of the tank(19lt) stable all over the winter months and is compact in size. Only got another because our tanks are growing.Would highly recommend.