Och I'm in the middle of doing some colour film developing and I have one more film to do, but I have a wee problem !!
Minimum quantity of Blix needed is 240ml and I only have 140ml left, can I dilute this chemical with 100ml water and extend dev time to compensate?
Bein part Scot myself, I can understand your concern, but it might do more harm than good. Film blixes are on the very ragged edge of being able to blix properly anyway and I don't recommend them. So, to beat the problem as best you can, fix the film first in a good neutral pH non hardening fixer. Use about 6 minutes at 100 F, then wash 6 minutes at 100 F and then use the blix for twice the time, but diluted with more of the neutral, non-hardening fixer, not with water.
That "might" work. IDK. Better than nothing.
Och Photo Engineer, av got Tetenal superfix for B/W, would that doo ???
It depends on hardener (none required) and pH (must be 6.0 - 6.7). If it fits that, you are ok.
I take it that 240ml is required because that is the requirement dictated by either the tank size or because you are using inversion agitation. As a Scot you might want to consider a Jobo rotary processor and Jobo tanks which only need 140ml for 35mm. Saves a lot of chems in the long run and gets temp spot-on
Of course it might be a 120 film which does require 240ml even in a Jobo processor which you might have and you can disregard everything above.