For this reason, we recommend a 12-month filter replacement. Although we have the world’s best filtration media in generous amounts, any filter, no matter how good it is, is a ‘toxic waste dump’ collecting the toxic debris in your water and preventing its passage into your body. This debris remains in the filter and eventually blocks the filter. Some cheap filters do not block up because the carbon they use allows ‘tunnels’ to form, which means water still gets through; it just isn’t filtered. We’ve seen this on too many occasions; people assuming their filter was still filtering when in fact it was a dangerous, potentially microbe infested waste dump.