Heating and thermometer placement in tank

So I have a small problem, in my 240 liters I have the input of the filter on the right backside corner of the aquarium and the outflow on the opposite side, the heater is right near te input and the thermometer is right bellow the output but the heater is set and calibrated at 25 celsius but the thermomether shows a constant of 27 celsius, I was thinking maybye the filter absorbing all the hot water from thre heater and throwing it right above the thermometer if maybe that's the cause and if that's it where can I put the thermometer to shoe an accurate reading

 

I bought a digital thermometer online from China for cheap. Kind of like a scanner gun at a supermarket. When I mistrust in tank thermometer Readings I point and shoot and confirm

 

I usually use those cheap digital thermometers at the furthest point from my heater when needed. My tanks all use the Fluval E series heaters (which are getting hard to find here in the US for some reason) and I’ve found the digital display on them to be very accurate so I don’t spot check them much anymore.

 

Maybe try putting the thermometer where there is little flow.

 

I would swap them.

Heather at the outflow en thermometer elsewhere. In that way your not "heathing" the filter amd will the heath better be gradually divided