I have upgraded my well water system with the large 4 1/2" x 20" carbon block water filters like these.
I use two of them plumbed in parallel to avoid any pressure drop.
I’ve always assumed that these should be replaced once a year, but perhaps that’s too often. Or maybe it’s not often enough?
Since these are carbon block filters, the color is not easy to judge like the single 11" filter that I used to have, even after a year of use.
Yes, I realize that these filters are a bit of overkill for a home well water system, but changing filters once a year or so is MUCH better than changing them every month or three.
My incoming well water is very good quality which leads me to believe that yearly changes might not be necessary.
If I install two pressure gauges on the input and output sides of the filters, would this give me a better idea of the condition of the filters? If so, how much pressure drop would I expect to see when the filters should be replaced?
No. The carbon works by adsorbing the chemicals out of your water. If any plugging is occurring that just means you should install a particulate filter in line before your carbon and you can use pressure gauges to determine when to replace that filter. The best way to determine if your carbon is spent is to test your water for the chemicals you are looking to remove and replace the carbon when you start to see the levels increase. Depending on the testing schedule you choose and the chemicals we’re talking about you may notice a taste difference as your first indicator of the carbon failing.
The well water has been lab tested several times in the past and the results have always been excellent with the exception of coliform. I fixed that with a UV sterilizer.
When I was using the old 11" filter, it would turn almost black and have a lot of sediment in the bottom of the housing when it needed changing.