SC8000 compellent and vmware

Below is my current situation and looking for help on how to reclaim the free space on the storage.

We have installed VMware esxi 6.0 connected to storage SC8000 compellent.

Have allocated 2 TB of volume to VMware cluster but it is occupy disk space of more then 3 TB. How to reclaim the space.

On my research, I found that for windows server there is a tool but not for VMware.

This disk space keeps on increasing because when ever we delete any VM our of strorage from VMware it does not get deleted out of storage and keep increase the disk space.

I am attaching  a snapshot of what I have right now.