Mystique Submersible Aquarium Heater, Auto Thermostat | Adjustable Temperature

This heater works great. I have it in a bio orb 3 1/2 gallon tank and the it has stayed 75 degrees. It is the best small heater I have bought.

Great little heater for my jungle bubble! With cooler temperatures setting in my warm weather fish and plants are thriving. This heater is just as described and works great! I really couldn't find a heater designed for under 5 gallons- but when I came across this one I had to give it a try!

Read through a bunch of reviews for heaters for tanks, ours is 2 gallons. Wanted one that would regulate vs stay on the whole time. This one does that and we haven’t had any issues. Only thing is the dial which you set the temp seems to be a bit of an underestimate of how warm the water the water will heat up, ex if on 77 degrees, temp may actually be 80 degrees but just have a good thermometer and adjust a little as needed. I use a different thermometer than the one this came with. Overall, just what we needed.

I have a 40 gallon planted tub/pond and even though it's surrounded by two feet of dirt and stone, and planted around the edges, I didn't want to lose my fish due to weird weather with hot and cold spells. This kept my pond at exactly 80 no matter how cold it got, my plants are flourishing in winter. ( Wisteria, Anachris, Java moss and Java ferns, plus duckweek) my fish are fat and happy.

Very stable temperature, very easy to setup, and it keeps a 10 liter (2.5 gallon) tank at 25 C (77 F) in an environment that swings from 10 to 20 C (50 to 68 F). The scale on the knob is very small and hard to read, and not perfectly accurate. (It's not meant to be accurate anyway, the exact setting also depends on room temperature and tank size.) Just be careful to increase temperature gradually and use a thermometer, and everything will be fine.

We are using this heater to keep a 5-gallon water bucket from freezing in a chicken coop.
It is well made and doing the job. We have not had any sub-zero nights yet but I expect it to work just fine.
We keep the entire heater submerged and have the temperature set at the minimum temperature. I have never actually seen it heating so I am confident that the 25-watt element is more than enough to heat 4-5 gallons of water in outdoor temperatures.

This seems to be a good heater. I originally had it in a 1.5 gallon for a few weeks while i got a 6.5 gallon ready for my betta and some tank mates. I decided to transfer it to the 6.5 Gallon to see if it would hold consistent temperatures without always being on and it works fine. I don’t believe that the build quality is good enough for it to be “100% submerged warning” and be water tight so i've kept the main body submerged but left the part with the controls and the cord slightly above the water level and again it’s been fine. The heater is on the right hand side in the background of my pic.

Heater is inexpensive, which is great! Is nicely designed and manufactured - that is, it does not look cheap. I placed it in my tank and it works as expected. Even comes with an easy to read thermometer, which is a very nice addition. I will buy another one of these!