hd Memory/ram

I have a problem, last week i looked in my hd and there was 207gb free space, i always try to keep my hd clean so not to clog it up with rubbish i dont need. I looked again today and there is 178gb free! I ran a diagnostic on the hd utility that says 53.8gb used from a 232gb on the hd. i then ran jdiskreport which has told me that i have used a total of 19.8gb which means i have 30gb uccounted for?! Has anyone any ideas where it has gone?

Try this program:

id-design, inc. | WhatSize

It will give you a graphical representation of what is taking up space, including hidden and system files.

Many thanks. Done that, found a file marked as private with 30gb in it, full of "VAR" files dont know what they are, should i delete them?