Easiest & Quickest method for Balancing Hybrid battery

I tried to find the answer through searching but failed.

- Which balancing method can one use to easily and quickly (not days/weeks) balance hybrid battery pack after one or two cells are replaced?
- I have seen videos of hybrid automotive where he uses 3 methods— Prolong charger, equalizer cables and the method with two bars (all + on one side and - on other). Unfortunately his Prolong charger isn’t available in the EU. The other two methods is equalizing, not balancing; right?
- If you recommend some sort of grid charger, please mention its name and would it do the job all at once— meaning the whole pack or will have to do it per block/module?

I get an error code which says that block 4 is weak. It could be one cell in that block or both cells, I haven’t checked it yet.

The Prius concerned is from 2006. 330k km. Based in the Netherlands.

Thank you!