I guess the sadly discontinued 'Brita Aquaflor' type is what you're
after - I have nearly run out of filters now, and intend to refill
mine when they are finished.
You need to use mixed bed ion-exchange resin with a small amount
(5-10% maybe,) of activated charcoal. I expect most chemical supply
companies have these (I haven't got quite as far as sourcing the stuff
yet.) If you don't already have a suitable jug, just use a drinking
water model with the appropriate filter cases, but be sure to throw
away the nasty salt-based filter filling and wash it out well before
refilling. You'll have to cut the top off to refill it, but I should
think aquarium sealant would be suitable for reattaching it.
Hope this helps,
Peter
snail:Peter Cole,17 Wimmerfield Cr. :mailto:carnivor@bunyip.demon.co.uk
Killay, SWANSEA SA2 7BU, WALES :http://www.angel.co.uk/flytrap/index.htm
vox:+44 1792 205214 :ftp://www.angel.co.uk/pub/flytrap