50 Watt Aquarium Heater Submersible Adjustable Temperature Fish Tank Heater 50W

I purchased this for an outdoor waterfall feature that freezes over. I thought that I might try a heater and was concerned how I would prevent it from becoming submerged. I was pleasantly surprised to find that this heater MUST remain submerged!The past few days it has remained below freezing, and all the ice melted from the waterfall fountain. I may not need to bring it inside this winter.

I bought this heater after one in my tank broke, and I wanted a spare. I got this and it works great, no issues so far.

It is adjustable, you determine the setting. I don't trust preset heaters, and this one is a top dial style, but the temp you set it to is easily read in your hand, but not when submerged. However, it is completely submersible and uses real numbers, not marks, notches, or a stupid plain dial.. What is not good about this heater, and it is my ONLY complaint, is no on light.. Even the preset that came from an aquarium kit has a light so you can tell when it is on and functioning. This does not. I always use a photography thermometer on all my tanks to know what the temp really is. So far, so good. This product is only a degree or so off, quite acceptable. It's just if it wasn't functioning I could not discern this by sight. Thus I deducted one star.

This heater is just what my 10-gallon tank needed to keep the temperature at 78 degrees. We keep our house about 68 degrees and this heater is not constantly on so I think it is doing just fine to maintain the heat once it gets the water up to temperature. I'd say the temperature is perfectly accurate, but the section cups could be better. One sticks VERY well. I have a hard time getting it loose! But the other one I find myself having to push it back on to the glass every so often.

I installed it in my 15 gallon Betta fish tank when the water was at 73F. I set the heater o 82F. 12 hours later (overnight), the temperature was still sitting at 73F. The thermometer (pictured after 12 hours) is accurate because i double checked it with my food thermometer as well. I live in So California where we have mild weather, so it's not like the tank is in a freezing room. I'm tired of these cheap Chinese heaters so I will return it and get a brand name product instead.

Used on a small 10 gallon fish tank. Works great.

Is the light supposed to stay on all the time, or only when it is actively heating? I saw the light come on as soon as I plugged it in, but not any more. So I'm not sure if it is not working or just in an off cycle. UPDATE: It is working fine; it just scared me that it stayed off so long. Prior to this, I had a small heater that stays on and just keeps water 5-10 degrees above ambient temp. It allowed too much variation in water temp, so that it got too cool at times. My betta had gotten lethargic and stopped eating, and I read that can be because he is cold. SO...I bought this one. It is working great. My betta is much more active now, back to eating and swimming happily.

I love this heater, easy to use and adjust the temperature. I just wish the cord was a little bit longer. I have tanks size from 1 gallon to 10 gallons and this heater is perfect. I also have few half gallon tanks and i use this heater, just need to adjust the temperature to fit the size.The heater is good, price is good, long lasting and i am very happy with this product.