Lifehacker have a really interesting article on how you can save money on “disposable” carbon filters for your Brita water dispensers:
…with a bit of time and the right suppliesâ€”a sharp utility knife (and/or drill), a cheap polyethylene plug, and an activated carbon mix from an aquarium storeâ€”you can refill an old filter over and over again for far less cost.
Lifehacker actually link to an article on Instructables, so you’d be better off heading in that direction to see how to do this, but I find it’s always worth seeing what Lifehacker dig up on the internet. They often have some good time-saving and cost-saving advice.
It seems from the comments on the Instructables site that there are some possible complications when replacing the filter with your own carbon. It seems that there are some other active ingredients in these filters that won’t be reactivated by this method:
Please be warned that Carbon ALONE will grow lots of microbes and can make you very SICK!. Brita filter use silver as an antimicrobial agent. You can also add Activated Silver Impregnated Charcoal. Sometimes called Chlorgon, this adds chloramine exclusion and bacteria killing ability to the basic carbon.
The organic compounds that the carbon filter traps (which are held on the vast surface area of the carbon) can, and DO, rot. If you store your filter in the fridge, you should be Okay for a few weeks… however if you store your filter at room tempature (like you can with a Brita) they will start to rot within the week. The resultant water, would not be better than un-filtered.
A Brita brand filter contains Carbon, Ion Exchange Resin (probably a number of types – each have different attractions) and Silver (both impregnated carbon and metalic compounds (you can see the silver if you look closely)…
Virtually all retail available Carbon filters contain silver to guard against organic growth (rot).
Whilst Carbon only is OK. I would not recommend it unless water is stored in fridge. Your filter will start to have an OFF (mouldy) taste when the organics over-run the carbon. Discard at that point. I am not an infectious disease expert, so I don’t know how sick this would make you… (if at all) but please be careful.
So, as with all things found on the internet these days – take it with a pinch of salt. I have no idea of the voracity of these comments but it does seem that it’s not as easy as it looks.