Temperature Problems

[HappyGeorge]

I have now finished setting up my tank and both the U4 and the Fluval FX5 are running, its now been going for 24 hours with conditioned water, with some Nutrafin cycle and 4ppm of ammonia and getting a minimal nitrite reading already. Tested tap water just to make sure I wasnt wrong, so seems to be going in right direction but.........

I'm having problems with the heaters, I have 2 x elite 200W heaters in a 450l tank. Turned them on and set to 27 degrees, but temp went above 29, so adjusted down again but still creeping up and showing on my Marina Aquaminder as being 30.5 degrees have adjusted down to 22 degrees now.

Have tested the tank at various places and depths with no change and have used a meat probe which shows within a degree of what the aqua minder says.

Are these things notoriously innaccurate?

Have I missed something obvious?

Do I trust the Aqua minder and completely ignore the heater settings?

 

[Harlequins]

the 200w rena heater i got in my tank,is set at 22 degrees at the moment,and tank digital thermometer ans the stick on one are showing 26,if i turn it up to 26 the thermometer shows its 30 degrees,

so at the moment i'm leaving heater set on 22 degrees.i think its trial and error with some heaters,especially with the ones with just has a dial on top.

Has you're doing a fishless cycle,the temp is better set high

 

[craig855s]

Are the lights on showing that the heater is actually heating the water. My heater doesnt run at all during daylight hours as the room temp is 26-27 degrees therefore tank temp is the same,heater cuts off at 24

I find heaters (superfish ones at least) to be really accurate,when my heaters are set to 24 my tank stays at 24..unless weather takes them up..so winter is a time of no worries,summer however is another problem

 

[chrisrm]

I have 2 x elite 200W heaters in a 350l tank and had the same problem mine are both set at 22c and my water temp is 27c

 

[OldMan47]

Try unplugging both heaters and waiting a half hour. After that plug one in and turn the knob both ways until you get to the point where the pilot light just comes on. Now unplug the one you have set and do the same with the other heater. At that point, both heaters will be set for a little higher temperature than the present tank temperature. Now you can plug both heaters in and adjust both the same amount from wherever they are to move in the direction tat you want. Once you are close to the desired temperature, you can again bring both heaters to the identical setting and then do a final fine tuning of the temperature. Pay no attention to the graduations on the heater dial, they are almost useless on most heaters. I have found that my visi-therm heaters have a fairly decent temperature setting dial but even those will be a few degrees off.

 

[HappyGeorge]

Thanks for that will see what they have settled at when I get home and try what you have suggested.

Looking at some other forums it seems general consensus is that the Aquaminder is normally a good degree to degree and a half over as well.
I was inclined to trust my meat probe, which would seem to be the nearest.