ya you can do that. If your running different EC's/ nutes then you can still do it this way. get a couple of Wort chillers, stainless steel ones are cheap. some hose, insulated after installation is best ,an insulated cooler the larger the better (this is your cold water res.) cut holes in the top for output and return hose., a submersible pump. what you do is use the pump to circulate the water from the cooler through the wort chillers to the chiller and back to the cooler. works well and you'll set the temp of the chiller by the UC res temp, not the cooler temp. I added a quick drawing to illustrate
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