It works out £7-8 quid a fill on the scrubber, a 20kg drum of Sofno knocks out at around £55.
Unfortunately it doesn't get much cheaper if you buy in bulk - an instructor told me if you bought 14+ drums you can get them for £50 a pop. Then there's the shipping, which is why I always preorder mine from APD for pickup at the dive show.....
There are other grades of absorbent (larger granules etc) which are cheaper, but cos I'm a blouse I'll stick with the recommended product.
PS you're absolutely right about the Helium. To quote Chasey's big deep dive as an example, gas costs for the 102m dive (excluding bailout) would have been about £4 as a garage-fill, £40 at Dahab prices
