Stop bath stops the development, water slows it down over time. What drum are you using? I use 70ml of stop and 70-100ml of rinse water before 70ml of blix in a beseler 8x10 drum, constant agitation for all four steps, pre-rinse, dev, stop, rinse, blix.
Stop doesn't contaminate the blix, if I remember, blix contains acetic acid, the rinse reduces the dev carryover.
70 ml of dev does two 8x10, sometimes that is five trips thru the drum, four 4x5 test prints and a final 8x10. I use the blix for up to the equiv of four 8x10 prints. Kodak's data sheet alludes to blix capacity where it states the max number of print capacity per liter, but it isn't overly specific, (edit) 40 prints per liter for non critical applications.
This is all with Kodak chems and paper at room temp.