boxtech Aquarium Heater, 50W/100W/300W Explosion Proof Submersible Thermostat with Adjust Knob and 2 Suction Cups Suit Marine Saltwater and Freshwater (100w Suit for 10-30 Gallon)

I ruminated over what heater to get for my daughter's new 5 gallon aquarium forever and settled on this one. What a winner this is! I have been running aquariums for decades and heaters are always such an issue. They need to adjust well, be reliable above all, which has lead me to usually put my trust in Eheim Jagers (of all the ones I have used in the past the controls on these are just so reliable). But in every case I have always sacrificed the aesthetics of my aquarium in some way as they are large, bulky, and ugly. For such a small sleek aquarium like I got my daughter I couldn't have such a dominant feature. So, I went on the hunt for something small, maybe something I could even hide in the filter compartment of the aquarium, and I found this little guy. It is fantastic! It is so small, aesthetically simple and even fit in the filter body so I don't see it all! I even ran 2 thermometers for a day to ensure even heating between the filter body and main tank. Flow was good, so I was with in 1 degree F. so perfect!Pros:Very compact, won't overwhelm the aquarium.Good controls! precisely warms the tank, I don't notice more than .5 degree in temp swing throughout the day.external controls, not having the controls on the heater element is great, no worries of them getting gummed upLooks good and hides well.Cons:While I don't know yet, durability. As of 3/2019 I haven't owned it nearly long enough to really judge its durability. And the equipment hasn't been around enough for others to really judge either. For me to give it the OK, I expect 5 years+ of service from it as that is what I expect from any good heater, before I prophylactically replace it before it goes bad. I hope it really lasts, because I love this thing!Update: 9/20: Now having owned 2 of these for about 2 years, I am impressed. they still work. They also still maintain a great constant temperature. There has been no temp drift on the thermostat to compensate for like with other heaters I have owned.

I did not realize, or maybe it wasn't explicitly called out, that this thermometer displays Celsius only. Minor irritation, but to ensure I didn't actually fry my fish, and b/c I'm not up to speed on my Celsius-to-Fahrenheit conversion, I Googled that shiz. Anywho, just know it's easy enough to do that if you need to.This heater is super compact, which I love. I have it in a 9 gallon Fluval Flex, which has built-in compartments in the back and so I needed a smaller heater to ensure it'd fit well in next to the pump, which shares the same compartment.It's in there, working great, and there's room to spare. I've been closely monitoring the temp of the water with a separate thermometer and so far it's holding steady at the desired 78*.The only thing I really am not a fan of, is that the cord is thick and round, instead of a flat cord. This makes it a little bulk in sitting nicely in the pre-cut part of my aquarium lid, but it's also not something I even thought about either, until after it arrived and I installed it. Also minor inconvenience, but just know if you have an aquarium kit w/a pre-cut area for cords to come from a lid, that is something you'd want to take into consideration.All in all, it's working great and doing its job.

This heater took my 55 gallon aquarium up to 100 degrees and killed the fish. don't trust it. this was in less than 8 hours. I placed it near the filter for water flo. It should have shut off but was still on.

I placed this 50 watt heater into the hidden filtration stage of my Marinland 3gal cube aquarium. It quickly provided a steady 75F for almost a week now. That is exactly what I set it for. Very happy with this (and so are my fish).

Works great, I love that the controls are outside the tank on the wire makes for easy adjustments.But Always use a seperate thermometer for accuracy.No heater I've ever bought has been accurate according to the numbers displayed so I don't take this as a product fault. But just a common issue.

Very happy with this heater! For one it’s size is amazing! I almost thought I got screwed when I opened the box and saw mostly wire until I pulled everything out & saw the small heater! And it’s white sleek look is very pleasing - not too obnoxious in the tank like a lot of other heaters. And the temperature was been fairly consistent I’ve been fine with the temperature. It mostly stays around 80.8 but there will be some times where I check it’s bumped up to 81 degrees but it’s never changed from those two temperatures. Again not a big deal to me but some people might think differently. Overall I’m very happy with this heater and even more so about it’s quality at such a nice price.

This heater had been jacked up for at least two or three days(100w). Not only did it kill my female small Angel guppies that I breed; It also killed my little runt molly. Out of 3 sets of fry, one was borned and never grew. His brothers and sisters are 3 inches long. He never reached an inch. Yes, I was late returning it, but that was only because I seriously considered taking you to court. Your 300 w is still in the box it came in. I will keep it as a reminder of you

I am really mad. I ordered this product back in June and we didnt hook it up. We just hooked it up a week or two ago and everything was going fine. It's nice and slim and I like how it looks but then today our temp in our tanks was at 90 degrees and the heat was still going. I turned down the temp on the knob and the heat was still going.. so we had to unplug it. Scares me to know my gish could of died if I wasn't home. And hes still not feeling well now. I added some cooler water and have no heater in there for a bit to let the temps come down. Very mad I cant return this awful Chinese made product. There's Chinese writing on it.. so ita cheap. I'm gonna stick to the name.brands I km now and trust..