You can craft a series of upgrades to increase the capacity and durability of subsequent tanks. Tier 2 tanks can hold 16 buckets.
Tier 3 can hold 64 buckets.
Tier 4 can hold 256 buckets and tier 5 can hold 1024.
This is a great mod for mass storage of liquid and the liquid can be easily retrieved from the tanks via an empty bucket or if you have a tube transfer mod already installed. This mod also requires an additional API installed found here.