same here. i set it to -1.
However, when my chiller kicks in and cool the water, after awhile, the thermostat on the chiller shows to the preset temp(26)
But my tank shows 27. Nvm, the chiller kicks in again, a short while later, thermostat shows 26 again, but tank still 27. the cycle contiunes.
After a day, tank shows 28, but chiller still shows 26.
What could be the problem?