How big is an "F"

[Dibbler]

having a group round here who only use Balloon Helium(bHe) in their diving, bought themselves, decanted themselves and topped up O2 & Air locally (they are regularly doing sub 50M Dives) and are all still alive

Personally paying AU$120 for a LDS 21/35 fill I thought I'd ask about a bit. Now the 2 LDS's I use both are of the opinion that bHe is no good due to the potential for impurities etc. However I recently bought an O2 analyzer from what I would consider an industry 'wholesaler' and looked a pretty clued up bunch at that, they design, manufacture? & install Gas panels and compressor systems the guy at the factory said 'there' nothing wrong with it and we use it all the time' for perspective they have their own Hyperbaric chamber (For medical HOT only)

His take on it was that its not a problem and he no problem recommending it. The difference apparently is you dont get a certificate with it but for all intents and purposes its the same.

Now obv a LDS has a vested interest from a liability standpoint, but I suspect its like a lot of other things in this industry, scaremongering tactics.

Now i'm not doing enough tmx diving to worry about it but there is a Au$50 saving per fill using bHe. I've since found a LDS that banks 21/35 and can top-up at AU$4.50 per 10 bar on Twin 12's so a top up is Approx $AU50-60..

Just an observation, any information is worth exactly what you paid for it.

edit: a cursory glance a the BOC website shows bHe at 97% He and 3% Air & Medical He at >99.99% He so who knows...
https://boc.com.au/boc_sp/au/safety/...sheets/027.pdf
https://boc.com.au/boc_sp/au/safety/...sheets/049.pdf