Sudden Temp Spike?

[FreakShow]

I am running a 12G NC DX with Stock lighting. Swapped out the stock pump for a Mini-jet 606 and added a Micro-jet 450. Ebo Jager Heater 50 Watt set at 78.

 

On initial test run, temps went down to 78.5 at night and never got over 81 during the day after a 12 hr photo period with the feeding door closed. Ambient temps in house at around 74. This was all good for a month and 1/2.

 

There has been no change in ambient temp, heater setting or lights but I came home the other day to an 85 tank.

 

I quickly turned off lights and opened the feeding door. Temps dropped to 83.

 

I now leave the ceiling fan on full, and leave the feeding door open and the temp fluctuates between 80.1-81.5. That is a good temp range I know, but what would cause the sudden change?

 

As soon as I shut the feeding door the temp starts to rise, day and night. Pumps?

[lgreen]

you might double check your heater. compare what it is set at with a thermometer and make sure it isn't comming on when it shouldn't be. sometimes heaters are just a hair bit off.

 

you may have to find a way to prop your lip open an inch or two.

 

a box fan or clip on fan near your tank might help a bit too.

[Sparkling_Surfer]

Don't keep your feeding lid open if you have any fish...I learned the hard way (and it wasn't open more than 1"!)...

 

I keep a fan blowing on my NC all day and it keeps it between 80-82.

 

Not sure why the temperature changed all the sudden.

[FreakShow]

Thanks SS and lgreen, I have been reading all the temp related threads for NCs. I do have a Firefish who is a notorious jumper so I whipped up this in about 10min:

 

A little left over from the bottom of my Cichlid tank. Its cut to sit snug in the opening. Now I know that if he really wanted to, he could probably dart right through one of those openings but it would be a lot harder. No problems yet.

 

I did pull my heater today and lowered it one degree to 78, cleaned out some macro algae that got into the pump compartment and cleaned both pumps. With the lights off the temp is hovering at 80.3 with the door shut. I will watch it tomorrow with the lid closed during the photo period.