I've used the Halo G6 in the past and thought it, and their cartos, were great for that size and form factor, but I didn't care for any of their liquids. I do know that there are some who are allergic to PG, so I would definitely suggest getting some sampler packs of 100 VG liquids. Virgin vapor is all VG, but some of the vendors mentioned in some of the other replies let you indicate the pg/VG mixture and they may be less expensive than virgin vapors.
The other thing to check, as mentioned above, is the inhalation technique - though if you've been using Blu's for awhile, this may not be the issue so much as the pg/vg mixture.
I hope you are able to find some liquids that will work for you!
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