Water Filter Advise

myredracer wrote:
Jbarca, what's the story on filters that have silver or an anti-microbial agent in them to help kill bacteria and organisims? Is it correct that some filter media are more resistant to bacteria growth? I think I read that polypropylene is better in that respect and that paper is not good?

Should an RV filter be tossed out once a year regardless even if it's had low use?

Red,

Here is what I know. If we happen to have a RV'er who is a water treatment person or a microbiologist they may add some more.

Silver and KDF are used in carbon filters to create an environment where Bactria does not like to reproduce in. They call this bacteriostatic http://en.wikipedia.org/wiki/Bacteriostatic

http://en.wikipedia.org/wiki/Carbon_filter

http://www.bestek.net/silver.htm

http://en.wikipedia.org/wiki/Kdf-55

http://www.kdfft.com/products.htm

That said, not all carbon filters have this feature of adding silver or KDF. Bacteria actually really like to grow in carbon filter beds. I have heard some RV'ers after a campout take their carbon filter that does not have silver or KDF in them , drain it and put the element in the freezer between camping trips to help keep the filter element from growing out of control. I have no background on this practice but understand they are using the low temperature to not allow the bacteria to reproduce. I myself would avoid using that type of filter on a camper if I was only weekend camping. Full timers that keep flushing it all the time are in a different set of conditions.

I too have heard the all plastic filters (polypropylene etc) are better over paper as the paper creates a bacteria problem. I "think" the issue is some papers being made from an organic substance creates a food source or a place that bacteria can harbor in the poris structure of paper. Plastics do not have these 2 issues. I am not 100% sure of the reason, however I believe these 2 areas are part of the problem.

How long should a filter be used? This partly depends on the type of filter and how it is used. 1 year of use regardless how many gallons have gone through it is a common recommendation that I have seen. Others are 3 months, my home fridge filter is 6 months. If the filter cannot be cleaned, then 1 year may be too long pending what it was subjected to. If the filter never had water in it, then I do not know of a shelf life that it cannot be used if it is a year old. Only if it has been in use. That said, my ceramic/carbon filter with KDF that are dried out and stored cool have gone over a year. I would not think of doing that on a carbon element with no KFD or silver in it.

The problem is there is no good way to know how much sediment or bacteria it was subjected to and how imbedded it is on non cleanable filters. And then there is materials of construction. Some filters may not hold up being wet that long.

If the manufacture states they have a 1 year in use life, then they have some kind of justification to base it on. And it may only be good practice so the filter does not fail in service not knowing how old it is.

Hope this helps

John