I got hit with this for the first time a couple weeks ago. I mix up a 5L XTOL kit and put it into 5 1L datatainers. I dilute 1:1 and throw it away after the first use (this works fine for 6 4x5 negatives in 270mL of the dilute solution).
Originally Posted by dpurdy
When I got zapped I was switching to a new bottle of XTOL at the same time as I switched from TMAX-100 to TMAX-400. It took me about 3 batches of film (the second two being test exposures after the first 6 sheets were ruined) to realize that the problem was the developer not my developing time. The bottle was completely full and closed tightly (though apparently not as tightly as I thought) but was mixed 5 months earlier. The next bottle I grabbed (mixed at same time) works fine.
I'm now entertaining thoughts of a switch in developers.