Does vinegar react with tap water?
Acidic acid (vinegar) does not react with water, and it is not soluble in water. The gel and white bloom may come from a reaction the acidic acid with minerals such as calcium that may be present in the dehumidifier. the gel could also come from the breakdown of the chitin cell wall of the fungi. If the white bloom appeared within a minute or two of the addition of acidic acid it was most likely a reaction with minerals or other compounds.