Mr Hjelc's setup is really phenomenal.
My best guess is that he is  using a big water reservoir and a strong submersible pump.
So, while mining he is also supplying his building with hot water.
25 degrees on the miner means the water that is circlulating is input to the system at close to freezing temperatures.
Regardless, very impressive. Mr Hjelc, due to such high concentration of power and chance of sudden steep rise in temp in case of possible failure of the cooling system I would hope you have taken all necessary safety precautions.