Hydor Theo heaters = Coral Killers

 

My main floor house thermostat is set to go down to 65F overnight... I have (2) 300w Ebo Jagers in the sump heating a total of about 140g of water volume. They are set at 77F. The lowest my tank gets is 76.8F at about 8AM. Once various lights start kicking in, my temp gradually climbs to a high point of 80.2 late afternoon... that's a 3.4F total swing, which I am OK with (and the tank inhabitants seem OK with it, too)

 

Point is, maybe 2 weeks ago I inadvertantly left the heaters unplugged overnight after a WC. The next morning, the tank temp was all the way down to 72.1F!!!

 

Going from 72.1 - 80.2 would be a 10 degree swing every day  too much IMO...

 

So...how do you "heaterless" guys avoid those kind of low temps (and temp swings) when the lights are off w/o a heater???

 

 

 

Me the Math guy, too

 

But I get the idea. Your house temp is not so low, so your tank temp wouldn't go too low...

 

Got It

The tank temp ran about 79-82 in the summer and 76-79 in the winter. I didn't experience large temp swings without a heater on my display tanl (2x175w MH, 2x140w VHO).

 

My smaller tank in the basement was a 65 gallon with only PC lighting. It stayed about 72-76 year round w/out a heater.

 

I don't have enough experience in my new house yet - in fact, my tank is still on the concrete in the basement! Temp is about 75 right now.