Hi,
I have never been faced with that problem before. You may wish to call the irrigation contractor in your area that installed the syste, or if you installed it, then you may wish to talk to a contractor or do some research on a type of filter for your concern.
Sorry i couldnt be a further help!
Thanks
Ray
Rays Above and Beyond Automatic Lawn Sprinklers
Thanks
Ray
Rays Above and Beyond Automatic Lawn Sprinklers