I have a Katadyn hiker pro. I used it for the last time was two years ago and then I stored it without following the procedure for long term storage. This procedure consists in using it with water purified with tablets and should serve to clean the filter from bacteria which eventually can grow. In a month, I will need it for a trip to Africa, so what should I do with the katadyn? Use it as it is? Replacing the filter (that is rather expensive)?