View Full Version : Question about substrate / undergravel heater algorhythm

01/30/2008, 04:18 PM
Hi, Michael and Matthias.

I finally got 'round to hooking up my in-sump heater to the system, and after observing it for awhile I'll also hook up my chiller.

Now that I'm paying attention to it, I'm confused about why the substrate heater (I assume this is an undergravel feature that I've never used in my life, admittedly) turns on when it does. For example, there are times when the temperature higher than it should be (e.g. the cooling symbol is ON) and the undergravel symbol is also ON.

For example, my tank temp. is currently at 26.3, my nominal temperature is 25.6. Hysterisis is set at 0.25. The chiller is on (as it would be if wired into the profilux, which is displaying a * symbol), but the profilux is also displaying ~ symbol.

Having never used an undergravel heater, I've no idea why this cycle exists. If I do choose to add one, however, I'd like to know about the profilux's behaviours with respect to temp settings.


Matthias Gross
01/31/2008, 01:25 AM
I assume you activated the "summer circuit" for the substrate heater.
This function ensures the circulation in the substrate even when heating is not necessary (during summer). Please read more in the manual.