After going through the entire mod, finally getting the abyssalnomicon, and then 8 statues and 1mil PE, did the ritual of cleansing only to find it only cleared 9 chunks...
It would be nice if the ritual cleansed the whole biome, or a bigger area, or at least give the option to increase the range in the config

The problem with cleansing a whole biome is that the size and shape of a biome is not predictable, not to mention the strain of iterating over a large area and replace blocks (I did a little test with tweaking the numbers the other day, and a 12x12 chunk area is 9437184 blocks to go through, and while my computer did fairly well with 180 ticks skipped, others may not do that good with iterating nearly 9.5 million blocks).
I've done some tweaking and optimization to the code, and in its current state it did a 8x8 chunk area pretty well. Might have to do some testing on higher numbers in case of making it fully configurable, but 64 chunks should be a pretty good start.

Maybe you could do a delayed procedural thing, have it kinda spread and clean one chunk at a time?