B&W film processor mysterious spotting

[Calebsavage]

hello, having an extremely annoying problem with our black and white film processor (Copal CFP-3130 converted to black and white, similar in design to a Noritsu 400 series). for the last couple months we've had ugly spots all over the negatives that vary in size but are generally circular and extremely stubborn if not impossible to wash off. 

Here's a quick list of all we've tried: Replaced all 8 circulation pumps, replaced all foam and rubber rollers in the dryer, scrubbed all racks, ran machine with Hydra Blitz film processor cleaner, also ran it with Titan Blue processor cleaner, replaced (almost) all of the original hoses and tubing, removed scale from heaters, replaced filters, and even more unpleasantness. We've ruled out the replenishment system, ruled out temperature control issues, ruled out the chemicals themselves,and ran several dozen test rolls. Still the same result.
It looks like an oily type of contamination, we can see a sort of oil slick floating on the surface of the tanks and have tried carefully drawing off the surface of the fluid to catch any contaminants but it just keeps coming back. No matter what we've tried (even when running the machine with only water in all of the tanks) we can see a bubble or something in the sprocket holes of the film when it crosses between tanks.

I'm going absolutely bonkers trying to fix it... we've been developing 30-40 rolls a day of B&W by hand (the old fashioned way) and it's really not fun.
Any other suggestions for getting it running clean again? Replacing the machine is not really an option... plus everything seems fine mechanically but the spots will not go away no matter what we do.

Edited June 15 by Calebsavage

[davidlam]

had you broke a glass type thermometer and inside mercury went to the tank(s) ?

[Calebsavage]

On 6/15/2022 at 11:04 PM, davidlam said:

had you broke a glass type thermometer and inside mercury went to the tank(s) ?

no