Defective heater or thermometer?

[BettaBob]

So I have my 5 gallon setup with a tetra 2-15 gallon submersible heater. It has been running for about 48 hours and the thermometer is only saying it is at 74 degrees when the heater is supposed to keep a constant 78. I have the kind of thermometer that sticks on the outside of the tank. Im wondering if anyone has had any problems like this with either this type of heater or this type of thermometer. I am hoping it is the thermometer and also think it may be because the fish seem very happy and active. Just wanted to know if anyone had any experience with this before i went out and bought new stuff. Thanks!

[xxabc]

Mmmmmmmm two things:

One) The heater is pretty known for barely keeping up with the 78 +/- 2. But 74 really shouldn't be happening.
Two) It's most likely the thermometer. I always keep away from those kind of thermometers - i have the kind that sticks right into the tank. I have the heater, and it should stay at least 76/77. I think the stick on ones only measure the temperature of the glass, not the actual water.

[Chicklet]

Preset heaters, Depending on where the tank is located, the heater will reflex that,
Your only gonna get an average of 4 degrees more then the room is already at.

[doubleatheman]

Originally Posted by Chicklet

Preset heaters, Depending on where the tank is located, the heater will reflex that,
Your only gonna get an average of 4 degrees more then the room is already at.

The walmart heater (2-15 gallons is 50watts, it's not a constont on heater like some others. It cycles on and off like a normal heater, but you can't adjust the temp at which it turns on and off. In most cases 78 is thouht to be fine. It says on the box it can range by 2*f in both directions.

Saying it will keep the tank 4*f above room temp is not true, the other type of Heater (7.5) watt from petco will do what you said.

My stick on thernom also says the same temp, About 74-75. With my 2 gallon tank.

[BettaBob]

okay i will pick up a thermometer that goes in the water today and see what that says

[Chicklet]

Saying it will keep the tank 4*f above room temp is not true,

I guess the big bunch I have here all lie to me then too
I get an average from most of 4 degrees. the colder the room the more it will reflex this too.
stupid me thinking I had any idea what I was talking about.

[xxabc]

Originally Posted by doubleatheman

The walmart heater (2-15 gallons is 50watts, it's not a constont on heater like some others. It cycles on and off like a normal heater, but you can't adjust the temp at which it turns on and off. In most cases 78 is thouht to be fine. It says on the box it can range by 2*f in both directions.

Saying it will keep the tank 4*f above room temp is not true, the other type of Heater (7.5) watt from petco will do what you said.

My stick on thernom also says the same temp, About 74-75. With my 2 gallon tank.

Yeah, I think that's the Hydor heater that will do that. The Walmart (Tetra heater) sets it at 78 +/- 2, so it should do as it says. Although I find 76 pretty low, I can't say anything because it's doing as it should be doing, despite being the minimum.

[BettaBob]

yeah it is saying 74 though so that is why i am questioning it

[doubleatheman]

Originally Posted by Chicklet

I guess the big bunch I have here all lie to me then too
I get an average from most of 4 degrees. the colder the room the more it will reflex this too.
stupid me thinking I had any idea what I was talking about.

I just find It heard to believe that a 50 watt heater on full blast would not heat a small tank by more than 4* when a 25 watt heater could raise a similar size tank by 10* easily (example 3 gallons or so).

Other 50 watt heaters heat tanks larger just fine.

Possibly these heaters are defective?

I'm not saying your wrong, but my tank with the Walmart heater is 13*f warmer than my room, but then again my tank is only 2 gallons, So yeah I cant know for sure.

I'm new on these forums so take what I say with a grain of salt :) but from pure math and numbers that heater should keep the tank more than 4* above room temp if needed.

No hard feelings.

[xxabc]

Bettabob - wait till you get the in-water thermometer and see what it says. If it actually says 74 degrees, it's defective (not too rare with these type of heaters. Could be returned.)

Doubleatheman - What if someone's house just runs that hot? Lol. I think the smaller the tank, the warmer it will get with a heater. That's my logic anyway... lol. Mine is about 6*F higher.