Tank temps

[outtafocus]

I seem to be having temperature issues with my tank.

When my lights are on, my temp sits around 79.5. The problem is when the lights go off, my temp fluctuates.
I check my temp when I first wake up, somedays the tank temp is at my usual 79.5(ish) but other days I will see the the temp down around 78.5, I find that when my temp is down low my heater is not on. I have also seen temps in the 80.4's up to 81, but my heater is on. The room temp stays farely stable and the tank is well away from any drafts or source of heat. These readings are all with no lights on.

I believe my heater is staying on to long but also not kicking in early enough.
Heater is an Ebo-Jager 150w mounted on an angle in my sump.
All of my pumps and powerheads and running all the time so its not as if a timed PH is adding heat.

Has anyone else experienced odd ball temps like this? Or found Ebo's to kick on and off at weird temps?

Any suggestions would be appreciated.
What

[jws444]

I don't think a degree or two does much harm. It fluctuates a little like that in nature too. It could be that you're catching the heater at the wrong times. All heaters have a little slack to prevent it being 'too accurate'. If it didn't have this slack, heaters would be turning on and off every minute. Same thing for thermostats for home heating.

[outtafocus]

I have always been under the impression that any fluctuation was bad, but I guess that if I was using a mercury thermometer I doubt I would even notice the fluctuation. I am using the Coralife digi thermometer.
I will continue to keep an eye on ethe temps.
Thanks

[TheReefGeek]

You could use a controller, but not worth it IMO. You could also try a second heater, that would stabalize it a bit.

[rickjames]

My heaters do the same thing, fluctuate a bit, stay on late and go off early. I go from about 78.5 to 80.5 right now. Your temperature range is fine though, in fact IMO I think it is perfect.

[Willow]

stable tank temps are important, a controller is a good way to help keep a heater do what it should. you can get a ranco controller for pretty cheap.

http://www.automatedaquariums.com/ranco.htm

[outtafocus]

How stable is stable?
What is an allowable range?
I really dont see my self spending $100 for a controller unless my temps are really out of whack.

[dockrat]

IMO A temp controller is the second most important piece of equptment for your aquarium. there a little pricey... But last year i went away for three days to come back to find my tank at 89F one of my under powerd heaters (ebo) had stuck on all i was left with was 1600.00 of Reef Soup. The $$$ i could Have spent on the controller could have saved me $1600.00
its almost sicking... Oh well live and learn PLEASE LEARN FROM ME BUY A TEMP CONTROLLER.
kris

[Beermaster]

We dont even run a heater in the 180gal, when lights are on the Temps are around 82-83, lights out the temps are 78-79 just like in real life

[TheReefGeek]

You must be running a lot of (or large) submerisble pumps then?