Be aware of a couple of things you need to deal with when using TMax (and Delta) films:
Best practice is to use a rapid fixer, i.e., an ammonium-thiosulfate-based fixer; not a "conventional" sodium-thiosulfate fixer. The former always comes as a liquid stock solution, the latter is powder.
Fixer capacity is greatly reduced when fixing TMax and other tabular-grain films when compared to "conventional" emulsions (e.g., Tri-X or FP-4, etc.). So keep good track of your throughput and discard your fixer in time.
Learn to do a clearing test to determine the state of your fixer. Do the test with fresh fixer and a particular film. Note the time it takes to clear the film completely. The best way to do this is to place a drop of fixer on the film and let it work for 20 seconds or so, then dunk the entire strip in fixer, start the clock, and agitate, keeping close watch on the level of clearing. The spot with the drop will clear first. When the rest of the strip has cleared to match the spot where the drop was, note the time. This is your clearing time in fresh fix for that film.
Then, test clearing time as your fixer approaches exhaustion. When the clearing time approaches double that in fresh fixer, your fixer is exhausted and needs to be discarded.
Also be aware that TMax and other tabular-grain films need more fixing time than conventional films. Fix for at least twice the clearing time (which means you have to do a clearing test before each batch of film) or, since fixing film longer than the minimum is rarely a problem, do as I do and standardize on fixing film for 4x the clearing time in fresh fixer. This builds in the required fixing time for fixer near the end of its capacity and obviates the need for doing a clearing test before every batch of film through the fixer.
But do test for clearing regularly as the fixer nears the end of its useful life. Discard it before it reaches 2x the clearing time in fresh fix rather than after.
If your problem with pink stain persists even if your fixer is in good shape (I've had problems with TMax 400 for some strange reason), a weak alkaline bath before the final wash will do the job. I've used sodium carbonate, sodium bicarbonate (baking soda), sodium metaborate and even the spent developer as a pre-wash alkaline bath the remove the pink tinge. All work superbly, just take different times. You can easily see the results.
Hope this helps,
Doremus