Heater question inside:

[SVTChili]

Hello, new poster here!

My question is pretty simple actually and I'm sure someone has encountered the same thing.

My tank is a Red Sea Reefer 425XL and I'm currently running a 150w Cobalt Neotherm heater in my sump. Before anyone blatantly says that it's not enough heater for the tank, I live in Florida where the temperatures are warm year round and more often then not the issue is tank cooling, not heating.

Anyways, I keep my heater in the sump and set at 78°, which keeps the sump at exactly 78°. The display however is a little cooler at 75°. Is there a formula to account for the temperature loss between the sump and the display without spiking the temperature too much? I suppose the easy thing to do would be to adjust the heater to 80° and see how much the display increases, but I wanted to ask before I start trail and error.

 

[redfishbluefish]

With the amount of water flow, temperature should be darn near close to the same in the DT and sump. Your problem is that the two temperature measurements are not calibrated. They are the same! Now just pick one.

 

[SVTChili]

I measured with a meat thermometer to be sure and the sump is for sure 78° with a 3° drop to the display. Granted I measured at 6" below the surface on the display... you might be on to something here.