Last summer I took our hiking filter (Katadyn Combi) out on the Lakeland Canoe Circuit – my one and only use during the summer. Apparently after that I didn’t do the best job of putting it away – leaving some of that scummy lake water sitting in it for almost a year. That meant that when I took it out this summer it had an awful smell and some mould on the ceramic cartridge. New cartridges cost money (lots apparently) but it is possible to clean out your mouldy ceramic cartridge with a little time and a few simple at home ingredients.
There is lots of info out there on how to clean your filter – some people suggest bleach, some say you should just replace it, but I found this FAQ from Katadyn to be a helpful starting place. If you’ve hauled your filter out the night before your trip and noticed mould this isn’t going to work for you, but if you’ve got at least a week, then it is probably possible to clean your ceramic element. I had a lot of success with the following procedure:
- Take the filter apart – break it down into as many reasonable pieces as possible. With our filter, the cartridge comes out as well as the top part of the filter unscrews.
- Scrub the ceramic element with the (green) scrubbie pad to remove any surface mould. Rinse frequently.
- Rinse out the filter body and use a cloth to remove any mould from the inside of the filter body (if it has gotten to this stage, yuck). I think you could use a diluted vinegar wash here too.
- Put the filter back together.
- Mix about 2 TBSP baking soda with 2 L of cold water. Pump this through the filter – the “filtered” water can go down the drain.
- Take the cartridge out of the filter again. Mix another batch of baking soda and water and leave your filter element in this to soak for about 24 hours.
- Assemble the filter and pump 3-4L of clean water through the filter.
- Taste test – hopefully by this point it tastes normal.
Now – take the filter apart again (ceramic cartridge out, handle open) and place the cartridge upright in a sunny location (I use my kitchen window sill). Let the filter body dry completely and then store in the bag. Let the ceramic cartridge dry for about 1 week – I find that water stays inside even if the outside is completely dry. Store or use as normal now.
We used our filter when we hiked into Turbine and I was pleased that there was no lingering taste of either mould or baking soda after I had cleaned it. When we got home I made sure to leave the cartridge out to dry for at least a week so next summer it isn’t a problem!