Fermentation Chiller

[BuckyB5]

First time posting here.
Problem:
I have a medium Brewha 4-1 BIAC and a Spike CF-10 conical with TC bundle. The BIAC has been great so far but as it’s starting to get hotter outside I’m having trouble keeping my fermentation temperatures under control. My first solution was to modify a 5 gal. Igloo water dispenser to feed a non-submersible pump that links into the TC that controls my TCV and the pump. So far the answer has been to keep feeding the cooler ice to stay sub ambient but I thought there has to be a better way.
Solution:
I got my hands on a 3.5 cu. ft chest freezer and a submersible pump. The plan is to place both pumps (for the BIAC and spike conical) in the bottom of a old keg, fill it with a water mix (further explaination during the question phase) and run the feed and return hoses through the lid of the freezer.
The question:
What can I do to keep the water from freezing and destroying the pumps? The freezer likes to dip well below 32 degrees and even with a Inkbird TC, the pumps won’t constantly be running to keep the water moving.
Any help y’all can provide will be greatly appreciated.

 

[BuckyB5]

Update:
Mixed a 10% alcohol solution using 190 everclear. This has dropped the freezing temp down to approximately 25 degrees Fahrenheit. The chest freezer has also stabilized and I have it dialed in to 56 degrees. Fermentation has finally stabilized at 65 degrees and I don’t seem to have any issues anymore with over-shooting high and low. Pictures to come soon.