Green sludge? on negative

It's been a while since I've been in the darkroom so I processed a roll of film to test my chemicals. I developed film - Tri-X 400 - in Rodinal for 15 minutes @ 68. When I took the reel out of the Photo-flo I noticed something floating in the water. It was green slime. It was on the reel so I rinse it off and placed it in clean Photo-flo. When I cut the tail off to hang up, I felt the slime at the end of the strip. This is the only place where this exist. The film looks fine otherwise.

I know somehow the chemicals affected this part of the film differently. My question is why. Did it receive too much light before development?

Thanks,

Daphne

How old was the photo-flo? I think the green slime may have been biological growth (algae, etc.) that occurred while the photo-flo was sitting.

Not old. I developed four more rolls using the same chemicals and no slime. The only difference was the film. Fuji Acros 100 this time.

I go for algae too. (Need light though.) Maybe that slime was sitting stuck somewhere and just got lose and noticed that last run.

Film emulsion particles (gelatine) displaced from films or cutting / perforating may form in solutions such slime. Gelatin is a food for eating such organisms.
In terms of photographic effect can disrupt because it leaves no substance to reach working solution to the film emulsion. Or leave to respond only partially.
The use of developer solutions are not very old you are beyond this difficulty.
George