My sump is pictured below (Ruby cube). There is a probe holder at the bulkhead between the overflow (back left) and the refugium (front) sections. I originally put the heater in the return area. My theory was to have the temperature probe getting water direct from the tank. But I read several comments about not wanting the heater in the return in case that area runs dry. And I bought a heater that turned out to be too long to fit diagonally in the return area. As a result I put the heater in the overflow area. But now my temperature probe is downstream of the heater. That did not seem right. I moved the probe into the main tank overflow. Now I noticed a new problem. When I shut down the water flow to do maintenance, the heater runs continuously.
I would appreciate any thoughts you have. My thoughts were: 1) buy a heater that will fit in the return and go back to my old setup; 2) buy a second temperature controller for the sump, and leave the Apex probe where it is.
I would appreciate any thoughts you have. My thoughts were: 1) buy a heater that will fit in the return and go back to my old setup; 2) buy a second temperature controller for the sump, and leave the Apex probe where it is.