Aqueon 300w Heaters

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Habs33

Aquarium Advice Apprentice
Joined
Feb 9, 2020
Messages
13
Hello everyone,
I'm new to the forum. I just bought a new 75 g tank and bought two aqueon 300w heaters. I have them placed at opposite ends of the aquarium and by some water flow. I'm trying to get the water temp to 76 degrees and can only get it to 69.7. I have both heaters set to max (88). They are both turning on and off.
Any help would be greatly appreciated.
Jamie
 
Hello Habs...

How long have the heaters been running? It takes quite a while to heat that much water. What are you planning to keep in this tank? Aquarium fish will be fine in a pretty wide range of water temperatures as long as that temperature is stable.

B
 
One heater is a week old and was is a day old. I went over today and bought a different one and it's doing the same thing. It makes no sense to me. Water temp is saying 68.7. I have bother heaters set at 76band neither will come on. I turn them both up and they come one for a min and shut off.
 
Are you sure the thermometer isn't the problem? Have you tried maybe switching to another just to double check?
 
Ya I took it out and ran it under the sink and it showed the warmer temp.
 
Ya I took it out and ran it under the sink and it showed the warmer temp.

Hmm, looking up some reviews of it online it looks like this happens from time to time with them. Where the heater doesn't heat or is innacurate in the temperature. Maybe try switching one out for a different brand to compare? If the thermometer is accurate then the problem is with the heater itself and there's no much to do about that.
 
I swapped one out today for a different brand and it's doing same thing. I'll have to try diff thermostat but the water does not feel 76 degrees at all.
I appreciate the replies.
 
Hello again Habs...

I use the Aqueon Pro 300 heaters. Hard to imagine a heater that's better. I use two to heat my 300 gallon outdoor tank. I have several large Goldfish in it and the heaters keep the water temperature at 60 degrees during the Colorado winters. I would set the heaters at the desired temperature and position them near an air stone or filter and leave them for a week or so. They should get the water to 76 degrees. Have you performed a water change on this tan? It would help to maintain the temperature if you used water that was a bit warmer than 76 degrees.

B
 
Well hmm.. the only other thing I can think of off the top of my head is there's an electrical problem in your outlet... (seems a long shot but that's what I got.) You can test by taking a heater to a different outlet putting it in a bucket of water and seeing if it does the same thing.
 
I'm at a complete loss. Returned this heater and got another brand. It is doing the exact same thing. I had the other plugged into another outlet. My old 200w is staying on. My next option is to try a 200w.
 
I use HOBs always try to put my heaters under or beside the *waterfall* outflow so that the heated water is being *instantly* pushed around the tank as it heats. It took almost 48 hours to raise the temp in my newly set up tank from 65 to 80ish.

Something to consider too - I recently watched an interesting/informative video on YouTube on heaters and their lifespan. The creator was theorizing that it was the constant on/off cycle that affected heater life. In other words with a larger heater(300W) it is constantly flashing on & off because it takes a shorter amount of time to heat the water than a smaller(200W) heater would and it is this constant on/off that shortens the heater life. After thinking about it I am inclined to agree with him. I ALWAYS have a double filter & double heater and have noticed a significant rise in heater failure since I upped the wattage from 100s to 200/300s because I thought larger heater equals better heater. I think I am going to be scaling back on size again to see if that helps extend my heater life.
Anyway back to your *problem* - if you upped the size from 200W to 300W the heaters will flash on/off a lot more than a 200W would and if not *close* to a *circulating* water flow may be heating the water immediately around the heater to the set temperature while not circulating it around the tank
 
Thanks for the replies everyone. I am going back to the pet store after work today and am going to try a 200w to go along with the 200w I already have in there.

Hopefully I can get this figured out.
I will post after I try the new 200w. I have tried Fluval, Eheim, Aqueon so now I’m not sure what brand to try with the 200w.
 
So....I figured out my problem........I’m an idiot :)
Well, hopefully not really. I took my digital thermostat out a few times and ran in under hot water and it read a hotter temp so I figured it was working properly. Bought a mercury thermostat and the readings were much different than the digital one. So I bought a new digital one and put it in the aquarium. It immediately went up to 87 so I threw the old one away and turned my heater down. Water was down to 82 this morning.

Thanks for all the help. Lesson learned.....always double check thermostat.

Sarcastic comments towards me allowed :)
 
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