Okay - stupid Q time (because I don't know the answers)
It's my understanding that the bugs - like we get in coolant can't stand / don't like low temperatures, ………...if this is so, why not run a chiller unit on the coolant tanks - taking the temp well down.
We've all had steaming coolant tanks at the end of a shift, ……...and as far as I'm aware, the colder a fluid cooling medium is the more efficient it is.
Retiring to find tin hat.
Fair universal that living things or inorganic chemical reactions either one DO proceed more slowly at lower temps, but even so?
It ALSO tends to PRESERVE the buggers, so they are then lying in wait for warmup to activate them.
Chilling also tends to not be as cheap as heating.
"Tin hat" is not so irrelevant, either. Bear with me ...
Professional, "revenue" shops have made use of whichever of the proven methods (many!) suit their specific needs. There are entire INDUSTRIES have been working on that for easily a hundred years! With money. And laboratories, even.
Mostly, they have solutions. Already. LOTS of them.
"Smallholders", be they small shops, retirees. or hobbyists, are about as well advised to only MIX a "tin hat" worth of water-emulsion coolants at a go to begin with.
Don't WORRY about trying to make them last forever whilst sitting mostly idle.
Just treat and dispose of them more often is all.
Food-service industry used goods, or Asian market steamer or stock pot, bought new is all the "tin hat" volume worth of witches brew of Ho-Cut I actually need. Some use kegs or pails.
On casters, rack of tanks, pumps, filters and all. Not my idea. Saw some OTHER Pilgrim's clever example, PM or some other website - I don't even remember which.
Serves more than one machine, wheeled coolant service "truck" does.
One scavenge pump for recovery line off a sump.
One pressure pump for supply to the work.
Settlement & filter tank or tanks.
Clean(ed) supply tank. Gravity feed, even.
Preening & cleaning can go on at times when not at a machine nor even being used.
End of the day no machine even needs a coolant pump of its own, and that's even LESS money wasted lying about in sumps turning into corrosion and stink.