I'm tweaking power production in my pack so large boilers require distilled water instead of regular water.

Describe the solution you'd like
A section in the configuration file where I can specify fluids that boilers can accept;
#List of fluids for boilers to accept as water
["distilled_water",
"water_pure"]
(by default this list would just contain water)
Condensate (such as water output from the turbine) would default to the fluid at the top of the list.

Describe alternatives you've considered
I've asked Noppinoppi (MoreTweaker dev) about adding CT support, however this was not viable as the boiler water is hardcoded in.

Pulling a switcharoo and reworking the default water as 'distilled water' would involve changing all of the water generators in my pack (some of which are also hardcoded) and changing worldgen to use a different 'water' block for rivers/oceans ect.

while at first glance, this seems like a minor change, this could really open up possibilities for modpack makers to gate power tiers, through more than just recipes. However, to add this, you would need to break the hardcoded format for all boilers, It would take alot of work to make this work, and you would NEED to have tooltips to be clear as to what coolant is used.
But first, you need to ask yourself if breaking this long-standing format is worth the niche case

If its just for myself, its not worth breaking the format. If a few more people take interest it might be worth doing.
(tooltips ect I could handle on my end)

It shouldn't be too hard I think. I'll look into it when I migrated the boilers to the logic framework.