The current fluid storage disk can hold up to 2^31 (signed int) mb of fluids which seems a lot but isn't.
Fluids adds up more easily than items and 2^31 mb of fluids can be achieved quickly in a modpack envireonment.
Considering the name "infinite" i suggest that the disk go from 2^31 to 2^64 mb of fluid storage.

TL;DR

Upagrade the infinite fluid disk from 2^31 to 2^64 mb of fluids