MQ Titanium Alloy 500W Aquarium Heater for Salt and Fresh Water, Digital LED Display Submersible Heater with External Thermostat Controller, for Fish Tank 70-80 Gallon

Bought this aquarium heater for my 29 gallon tank. Filled with hose water and the heater read it was 60 degrees F. Overnight, the tank reached 76 (I have it set for 77). I think it went up to 90 degrees, then shot back down to 60 something. Easy to install. Hasn’t moved from where I placed it, even after re-wiring everything and moving stuff inside around. October 28, 2024 - Reaching out to the seller because my heater states it’s at 80 but it’s actually between 76-77. I had it running for hours and I’ve been checking temperature all day. Nothing has changed in my tank. Requesting a new one or buying a whole new heater from somewhere else.

I bought this a year ago for 2 of my oscars in a 55 they’re fully grown now and I’m building a indoor pond for them, I bought this heater a year ago and I still have it and it still works perfectly fine and keeps the water at the temperature you want it to be, warms up from 60° to 84° in about 40 minutes, I just bought another not because the one I bought broke but because the pond I’m building will need 2 this is a good product long lasting best value for your money sleek light weight easy to use

I bought this aquarium heater for my fish tank back in June so I could have it ready so when September came around I can put it in my tank when it starts to cool down in my area. It worked great for the first couple months and then all of a sudden today I wake up I look at the temperature And it’s almost 90° in my fish tank. I could feel the heat from the outside of the tank so I pulled the heater out of the tank. Make sure there was no clogs which there wasn’t or any debris on it at all. I’m luckily I caught it in time. It could’ve been bad for my fish , I was really hoping this heater would last at least a year they didn’t even make it three months. I would save my money and buy something else. There’s no reason why heater with minimal use should crap out in a couple months it keeps displaying error code E8, but yet in the manual doesn’t tell me what this code means so there’s nothing I can do to fix it and I miss my return window so I’m pretty much just stuck with this piece of junk that does nothing! Save your money by a better product. This one won’t last very long.

Here are some codes I found that likely apply but I have only seen the current temp, the target temp and E1. blue led means not heating, red led means heating is on: LL No.1 temperature sensor fault HH No.2 temperature sensor fault E1 The heater is not submersed E2 The heater is placed somewhere with bad water circulation-Components fault E3 The heater is placed somewhere with bad water circulation-Components fault E4 Flat power grid interference couldn't find anything on E8 seen in another comment I've bought three of these 500W. The first two were branded vivosun. the last MQ. The first lasted 3 years then just stopped heating, no errors, still reads temp only. The second, less than one year old is working fine. Bought a 3rd for winter backup this month. It shows 3 degrees hotter than actual. I was used to dumb heaters so when E1 showed up I didn't understand it. Turns out there's a sensor at the top and these units require complete submersion. My biggest issue was I was too lazy to read the manual and didn't understand the E1 code. I experienced this, make sure to tap bubbles out of holes if E1 persists. E2 means it senses an overheat condition > 96F. I believe usually caused by poor water circulation, or stuck on. I haven't experienced this, but I see at least one in the comments that has. E3/E4 seems to mean component failure or water ingress.

It’s good for big tank

WHAT A WASTE OF MONEY 🤦 I gave it five stars because I needed to warn people products that don't work or work but don't last, we bought this after I read every positive and negative review I figured I'd give it a chance and it worked perfectly until a month ago the date today is July 14th 2025 to give you a perspective, at the present moment it won't stop flashing and it doesn't stay warm, it's on and I can hold it in my hand underneath the water, so now back to searching for a submersible heater for my turtle tank, buy at your own risk.

I placed the heater near my wave maker in my 75 gallon tank. The starting water temperature was 72 degrees. It only took a couple of hours to reach the 76 degrees I set on the heater. I really like the temperature read out on the heater itself. It's lit up and easy to read. There's a red light that indicates the heater is on, and a blue light when the water temperature reaches the desired setting. Overall, this heater which is titanium and not glass or plastic seems to be very sturdy and well built.

Product did not last one month's time and I have to buy another one again I guess I'm not buying the same one it seems the way things go these days most items when you bought in the past when you were growing up would last until you're adult the refrigerator in our house lasted for 20 years people can't get two years out of a refrigerator now coffee machines we have literally bought five in the last 2 years it makes you just want to go back to percolating it wouldn't the stove I don't know who is in charge of making sure products last for enough time to where you don't feel burned but it doesn't happen very much anymore your product look great work great in the beginning but I think a month is not enough time to be happy with it what do you think please let me know and be glad to send me another one for free I will try it again maybe this one was faulty because it already says that my time is expired on trying to return it

The heater arrived after a long wait, only to find that it is an American heater with an American plug. This will not work in the UK because the UK mains voltage (230-240V) is approximately double the US voltage (110-120V). You would need a step-down transformer to use it here. Why even advertise these on the UK Amazon site if we can't even use them?? Dissapointed

The digital display is so easy to see. The best part is being able to change the temperature setting without going inside the tank. The heater is working just great in my 90 gallon tank. Obviously I have been using a very old heater.

The heater lasted 6 months before malfunction and heating the tank to 40C nearly killing all my fish!

Absolutely terrible... started to go crazy 2 mins after I put it in the water. It would turn the heat off an on rapidly and show temperatures from 70 to 84 within seconds.. woke up the next day and the display was blank. Waste of money

Muy bueno me salió este calentador, después de un fiasco con uno de marca reconocida, este nada le pide a esas marcas