In the later versions of NC, it is no longer always the case that it will output 4 fluids.
What used to be Hydrogen*475, Hydrogen*475, Deuterium*50, Oxygen*500 is now Hydrogen*950, Deuterium*50, Oxygen*500, Nothing.
CraftTweaker can't seem to support that, as it wants 4 outputs to see it as valid

Script
mods.nuclearcraft.electrolyser.removeRecipeWithOutput(<liquid:deuterium> * 950, <liquid:oxygen> * 500, <liquid:tritium> * 50); mods.nuclearcraft.electrolyser.removeRecipeWithOutput(<liquid:hydrogen> * 950, <liquid:deuterium> * 50, <liquid:oxygen> * 500);

NC 2.11
CraftTweaker 4.1.9

Adding null as the 4th output does not work either unfortunately.

Just tested and it does work - you need to add an additional set of brackets, so that your script looks something like ([...]), otherwise CT will not read the recipe correctly.

You're looking for something like this:

mods.nuclearcraft.electrolyser.removeRecipeWithOutput([<liquid:hydrogen>*950, <liquid:deuterium>*50, <liquid:oxygen>*500, null]);

You may want to check out the updated CT document for more info :)

However, I had forgotten that the old CT methods do not like nulls, so I will update them so that all the old methods still work when nulls are involved :)

Woops, I only checked out the Electrolyser section in the updated document ^^' Thanks!

No prob!