Issue with D-D temp controller/heater

[The_Reef_Doctor]

Hi folks,

Hoping you can help.

Recently started a new Red Sea Nano G2 XL (33 gal). Having some issues with temperature.

Based in the UK, current room temp approx 19-20 degrees.

Purchased and installed:

D-D Titanium Heater 150w
D-D Dual Temperature Controller

Tank was c. 24 degrees when first installed, desired temp set to 25 degrees. Heating symbol came on as expected, temp rose to 26.3.

However, the strange thing is, it won't come down. It's now been over 24 hours and still showing 26.3/26.4.

I've checked that it has been set correctly at 25 degrees desired temp. I even lowered that to 24.5 to see if I could get it to come down.

Checks done:

• Nothing installed in the chiller plug.
• Heater is in correct plug with sun symbol.
• Probe is in the rear sump but not too close to heater and not near any pumps.
• No other heaters running.
• Tried moving probe to another chamber - same reading.
• Wall radiator nearby is turned off and will remain turned off.
• Temp verified via Hanna Salinity checker reading - 26.3.

Any ideas what is happening here? Surely don't need a chiller in October in the UK?

Thank you very much.

John

 

[Reefing Madness]

 

[AmateurAlchemist]

What's your heating differential set to? If you unplug the heater does the temp fall? Do you hear the relay click on and off when the probe goes from warm to cold to warm?

I maintain the same same room and tank temps with the same controller and would be very surprised if other equipment was keeping the tank that warm!