So the probes are reading it 1f below the setting of the heater (82f), so I'm good with this for now. I have a "temp" replacement heater coming tomorrow (it has a very details out of water display for the current temp vs desired temp) - one of the better rated units, until I get my (1st) new shipment of the 300w Neo-Therms, and have placed a 2nd order with the same company for a 2nd set of the Neo-Therms, sine they are SOOOO freaking hard to find in stock (the 300w, anyway). Given that these lastest a good 5-6yrs, I think I can say I've been pretty happy with them. And using 2 of them, I now know how I can tell if something's off 
--- DS

--- DS