To the left is a photo of a pressure guage.  It shows that at  about 1 inch of water differential pressure our Type A filter begins to breathe.

The video below shows air bubbles coming through the filter with it about 1 inch under plain water (about the same pressure).

Our Type B and T filters breathe much more.

No need to be concerned about the transmissability of our filter patches.  They have been tested in the lab and proven by hundreds of mushroom growers around the world.

If you have any questions or concerns about mushrooms, spawn, bags, filters or any of our products,  you can reach Lou directly through our contact page or by commenting below.