fermentation temperature control

I have an idea I,d like to bounce off your noggins… I,ve been brewing for about 3 years now. ButI have a realy limited bufget. Recently my father gave me a contraption he had when he broke his leg. Basicaly its a cooler with a small pump installed and its original use is to pump chilled water though a device in his cast. I,m thinking of using this to control my fermentation temps.I,m thinking of using a slightly larger diameter bucket to place my bucket or carboy in, ataching an in an out hose to the pump and running ice water through the system. I need some way to control the pumps on off with the temp but not sure if i can aford a contrloer… any options? Thanks…Tank :cheers:

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