Heater Not Doing Its Job?

[windrunner9189]

I have an aqueon 100 watt heater that's preset to 78 degrees. it's in a 20 gal tank, right by the filter output, and it's been there for 2 weeks. yet.. it has failed to keep the tank 78 degrees, like it should. the temperature keeps fluctuating, 75-77 degrees. this morning the temperature read 75 on both my digital thermometer and the little thermometer stuck to the side of the tank. it was somewhat understandable, considering I had the fan on in my room. for future reference, should I be alarmed about temperature fluctuations hurting my fish, and what should I do about this? maybe add a small heater to the other side? leave it as it is? try to return the current heater and get a new one?

 

[Bumblebees]

I have an aqueon 100 watt heater that's preset to 78 degrees. it's in a 20 gal tank, right by the filter output, and it's been there for 2 weeks. yet.. it has failed to keep the tank 78 degrees, like it should. the temperature keeps fluctuating, 75-77 degrees. this morning the temperature read 75 on both my digital thermometer and the little thermometer stuck to the side of the tank. it was somewhat understandable, considering I had the fan on in my room. for future reference, should I be alarmed about temperature fluctuations hurting my fish, and what should I do about this? maybe add a small heater to the other side? leave it as it is? try to return the current heater and get a new one?

I usually keep two heaters, one by the filter, and on on the other side. Also a 20g. One is a present to 78° they other is adjustable set at 84° my tank stays a lovely 80° if its COLD outside, it might drop a degree. Are you sure the heater is not faulty? Maybe warranty it, and try another? I have also found that if you use warmer water during a water change, And increase the tank temperature by a degree or 2 during your a water change, The heater will have an easier time KEEPING the temperature up rather than RAISING the temperature. (Also can do this using a heat pad, or heated blanket, CAREFULLY wrapped around the tank and CLOSELY monitoring temp until it is raised)

Always raise temp slowly. A degree for every couple of hours.

 

[Wraithen]

How cold is your room? That heater is going to have a tough time unless that room stays at 70 to 72 degrees.

 

[windrunner9189]

I usually keep two heaters, one by the filter, and on on the other side. Also a 20g. One is a present to 78° they other is adjustable set at 84° my tank stays a lovely 80° if its COLD outside, it might drop a degree. Are you sure the heater is not faulty? Maybe warranty it, and try another? I have also found that if you use warmer water during a water change, And increase the tank temperature by a degree or 2 during your a water change, The heater will have an easier time KEEPING the temperature up rather than RAISING the temperature. (Also can do this using a heat pad, or heated blanket, CAREFULLY wrapped around the tank and CLOSELY monitoring temp until it is raised)

Always raise temp slowly. A degree for every couple of hours.

I don't think I can warranty it without the tank itself, i'm pretty sure. this heater came with a kit, and I really can't take this whole tank apart to take it all back. unless that's not the case and I can take it back on it's own.
i'll try a water change soon. in the meantime ill see if there is a way to raise the temperature enough to get it to, maybe, 79, then ill do the water change. I have a heating pad laying somewhere that I might be able to use

 

[windrunner9189]

How cold is your room? That heater is going to have a tough time unless that room stays at 70 to 72 degrees.

about 66 degrees with the fan on. ouch. ill turn it off
edit: it's now 71 degrees without the fan

 

[Dawn Michele]

I LOVE the Aqueon Pro heater's. I ALWAYS use 2. One on each end of the tank. They do a GREAT job.

 

[Tscott]

Your heater may not be calibrated correctly and some heaters have a 2 degree variance that’s plus or minus so up to 4 degrees. For some fish this is ok for but most it is not. What I did for my 90 gallon is buy two cheaper heaters and set them to 80 degrees and then I bought a controller that they plug into that has its own thermostat and set it to 79 and you can adjust the range on it so I have two points to shut it off it the heaters fail as the cheaper ones tend to do

 

[Wraithen]

I would just get another 50 watt adjustable. Multiple heaters isn't something most of us skimp on. I run 2 300 and 1 200 in my 6 foot tank. Its cheap backup, especially when your room might be more than 10 degrees cooler than your tank.