i have three thermometers sa setup ko. two at my sump and one at my main tank. one is a thermometer made by otto, the other one is the one with the hydrometer and the one in my tank is a digital thermometer by ocean free. here are the readings (with fans turned off):
thermometer only: 29 degC (sump)
thermometer with hydrometer: 30 degC (sump)
Digital thermometer: 28.4 degC (main tank)
the thermometers from the sump are only a few inches appart.
dahil kaya sa manufacturer lang to? i'm planning to buy another digital thermometer with a different brand tapos compare ko...