I have small herb garden (parsley, coriander mint and basil) that is watered from below by a hydrophilic filter using capillary action from a reservoir. This filter allows water soluble nutrients to be fed to the herbs.
The manufacturer of the filter use a special propitiatory additive in the filter that allows for excellent water flow. I need to know the the harmful implications of the material as they have stated the unknown "additive in the filter is not FDA approved". They will not tell us what additive is to protect their intellectual property.
My question is that will the herbs absorb the additive regardless assuming the additive is leaching into the water. Say that 1 ppm (parts per million) of substance X is in the water. Will the herbs absorb that and propagate it to their leaves. If so how much of the substance? (very rough estimate will do)