RDWC DIY Chiller Opinion Needed

I live in a hot, humid area, and it’s dead middle of summer. I have had problems with root rot unless I chill my water somehow. I have a big mini fridge that gets so cold it freezes water completely. I was thinking about making a stainless steel wort chiller, dropping the coils in a metal stockpot of water, and running it through the mini fridge from and back to my reservoir to cool my RDWC nutrient solution. I was thinking about 25 feet of 3/8 tubing, but I’m not sure what size water pump. Would this be effective for 15-20 gallons of nutrients? My reservoir and containers my plants go in are insulated with great stuff foam, and covered with Mylar (no Mylar on reservoir it’s outside grow area). Anyone tried this or have any suggestions?
I was thinking the nutes would cool quickly because of the metal transferring temperature, and the water around the tubing would be frozen in a day or two. So, I hope it would be effective in keeping my root temps down.

*I have had success using frozen milk jugs, but got tired of switching and cleaning them. I had used about 30 foot of polyethylene tubing coiled in a plastic container and then put inside a mini fridge before, and it worked pretty well. But last time I had hell with the water pump pushing it through the coils and back into my reservoir. I think it was kinked somewhere I couldn’t see when door was closed.


Lookup on utube for diy swamp or evaporated cooler for ideas.