How do I add an MDISK to an existing Volume

I have an IBM SAN Storwize V3700 release 7.2.0.3.

I've added 8 new disks and created a new MDISK3 using those 8 disks. The system automatically added the new MDISK3 to the pool MDISKGRP1.

When I look at the Volumes by pool and pull up the MDISKGRP1 I can see 2 Volumes - HyperV1 and Quorum1. When I pull up either the HyperV1 Volume or the Quorum Volume, I can see the first 2 MDISKs (MDISK1 and MDISK2). So how do I get this new MDISK3 added to these Voulmes?

MDISK1GRP1 shows 3 MDisks and 2 Volume Copies and says 3.18 TB allocated to Volumes and a Capacity of 10.90 TB

If I click on Volumes that will show me the total 3 Volumes that exist on the system, the strange thing is that the HyperV1 shows a capacity of 5.52TB (storage pool = MDISKGRP1).

This is very confusing... I just want to make sure that all the disk space I just added can be...