water filter for bob

[Timelord]

That bit about shelf life/expiry date is right. Carbon is not going to degrade anytime soon, especially when isolated from UV daylight. It is definitely X amount of litres passed.

Even so, this is not really accurate. It will depend on the quality of filter/thickness of the element and also on the amount of contaminants being processed through the carbon filter. If your water is fairly dirty, then it will not last as long. I would think that hard water will also contribute towards this. In this circumstance, the X literage suggested may be severely reduced before the filter either becomes clogged or becomes ineffective at cleaning the water.

If you try to select cleaner, less visually dirty water, that will help. If you think there may be a lot of biological organisms in the water, even though it appears clear - then this will also reduce the efficiency of the filter.

In a long term survival scenario, good tip would be to only use the carbon filtration device either in an emergency or after first taking other simple methods to filter or boil the water. Prior chemical tabs may not help for this, as the chemical & biological waste matter would still be present as the water passed through the carbon filter and could contribute to clogging up the filter.

Another emergency tip - THOUGH NOT RECOMMENDED UNLESS IN DIRE STRAIGHTS - would be that if the carbon filter has become clogged, maybe repeatedly after manual scrubbing(if this can be done), then it might be possible to shave some of the outer layer of the carbon filter away to expose fresher inner layer . Some filters may not be robust enough for this and so trying this could wreck those ones, so examination & care must be taken. I am not suggesting that this newer inner surface will be clear of contaminants, only that contaminant build up or clogging will be heavier from the outer layer inwards. This shaving action may allow a heavily used & maybe clogged filter to be used for a short time longer in an emergency situation. Hopefully other measures will have been put in place by a "prepper" or any survivor to not have to try this method.

The above is theory only and anyone who undertakes this does so at their own risk. I have put it down as it crossed my mind and it could be of use in a dire situation.

Regards, TL.
(always I.M.O.)