Water Temperature

[paulypaul182]

Ive just bought a 200 watt to go with the 300 watt heater for my 300 litre tank. Its been in there now for a good 2 hours. Both heaters keep going on and off but the temperature guages are only showing 22 degrees centigarde even though ive set both heaters to 26. What am i doing wrong? Is it anything to do with the filters flow direction? Have I bought a strong enough heater? Both are on either side of the tank to each other.

 

[minxfishy]

Hey mate, are the thermometers stick on the glass (outside ones)? or inside glass thermometers?

 

[blue acara]

You should check that your thermometer is accurate.
I have always found heaters thermostats to be innaccurate. Some heat too much, some too little. If the thermometer is correct then turn up the heater until it gives you the water temperature you want.
300 watts in a 300 liter tank is fine, try to position the filter outlet so that water flows over the heater, this will improve its efficiency.

 

[paulypaul182]

Hey mate, are the thermometers stick on the glass (outside ones)? or inside glass thermometers?

Yeah, ive got stick on ones and one inside tank one.

blue acara

I have a 300 watt and a 200 watt in the tank as someone said 300 wasnt enough. Last night I set the 300 watt to about 32 degrees but the water was 22 this morning. Im wondering if the 300 isnt working properly as the light never goes off.

 

[blue acara]

I'd say your 300 watt heater is broken, if it has been on all night it would have heated the water well beyond 22. You can check the heaters working buy putting you hand around it while its turned on in the water. Although this may be a bad idea as it could be damaged-

 

[Truck]

have you positioned the heaters vertical? if you have make it so there horizontal

 

[Schmill]

Does the inside thermometer (in the water), and the one stuck on the outside give the same reading?

Was it you that said that the tank was in a cold room (about 10 deg c?) If so I can imagine that there wil be a difference in temp between the water and the outside of the glass.
Also as others have said I would suspect the heater thermostats, you can try cranking both up a little and see what happens, although I've never known one to be THAT far out...

 

[minxfishy]

I would think the same, maybe the 300w is broken, be careful checking it, I would take it out, put it in a bucket of cold water, turn it on and see how long it takes to heat it up, if it doesnt heat it, then you know you have a problem. In the meantime, crank up the 200w.

 

[Schmill]

I'm not sure on the internal workings of these heaters, whether all the springy elements are linked together in series, (ie. one break and the heater stops working altogether), or if they are several heating elements in parallel all contained within one glass tube.
If the heaters are design as per the latter, I guess it would be possible for your 300W heater to only be running on 150W 'worth' of it's elements.

Although hang on... didn't you say that BOTH the heaters are switching on and off?

<Checks>

Yes you did:

Both heaters keep going on and off but the temperature guages are only showing 22 degrees centigarde

and also you did not:

Im wondering if the 300 isnt working properly as the light never goes off.

If both are switching on and off then they both think that the water is at the right temperature according to their thermostats, so if you want the water warmer turn them both up a bit.
If the 300W isn't switching off at all then it thinks it never reaches temperature. If you turn this one DOWN does it's light go off? If so the thermostat is good, so turn the 300W one back up to where it was, and increase the setting on the 200W. In THIS situation it's entirely possible that not all elements of the 300W heater are working.

 

[paulypaul182]

Right, Ive taken the 200 watt heater out of my 100 litre tank. The 100 litre tank is on standby at the moment to quarantine my new fish tomorrow. It has 2 plecs and a zebra loach in at the moment though so Im hoping this will work. The suspect 300 watt heater is now in the 100 litre tank and the 200 watt heater from the 100 litre tank is in the 300 litre tank. So thats 2 x 200 watt heaters in the 300 litre tank.

Ive always kept my heaters vertical (upwards not across) and have never had a problem before. It also hides unsightly wires as well.

Lets see how the next couple of hours go. That 300 watt has been in the tank since Tuesday. I thought the temperature wasnt rising because the heater wasnt any good on its on which is why I bought the 200 watt to back it up with.

 

[Truck]

well if you have them vertical they wont work propely as you know heat rises. and once the water has gone past the heating element it rises and goes past the thermostat and switches it off thats why if its on its side it works more efficiently. and theres less chance of you heater not working properly even at 45 degrees it makes a differene

 

[Miss Wiggle]

they work fine vertically providing there is a reasonable amount of flow rate around them.

 

[paulypaul182]

I'm not sure on the internal workings of these heaters, whether all the springy elements are linked together in series, (ie. one break and the heater stops working altogether), or if they are several heating elements in parallel all contained within one glass tube.
If the heaters are design as per the latter, I guess it would be possible for your 300W heater to only be running on 150W 'worth' of it's elements.

Although hang on... didn't you say that BOTH the heaters are switching on and off?

<Checks>

Yes you did:

Both heaters keep going on and off but the temperature guages are only showing 22 degrees centigarde

and also you did not:

Im wondering if the 300 isnt working properly as the light never goes off.

If both are switching on and off then they both think that the water is at the right temperature according to their thermostats, so if you want the water warmer turn them both up a bit.
If the 300W isn't switching off at all then it thinks it never reaches temperature. If you turn this one DOWN does it's light go off? If so the thermostat is good, so turn the 300W one back up to where it was, and increase the setting on the 200W. In THIS situation it's entirely possible that not all elements of the 300W heater are working.

Just checked the 300 watt and it only switches off at 18 degrees, the tank its in now is 24 degrees.

Ive just put the heaters horizontal to see if it helps. Ill have to get some more plants to cover them up I think

 

[paulypaul182]

Temprature seems to be rising now. I hope ive positioned the heaters ok. Ive lay them horizontally just above the gravel and behind some plastic rocks that I have. The only thing I dont like about where they are positioned is that I cannot see if they are switched on or not.
Tank is looking great. Im getting a few more plants tomorrow and then Ill post some piccys!!

 

[Truck]

nice to hear its working well now