|Ask The Expert: Testing for tannins
How do you test for tannins in water without a tannin testing kit? What are tannin filters and how do they work?
S. Kronfli, Water Depot, Ontario, Canada
Send your sample to a lab that can run tannins by a suitable test method.
Stephen R. Tischler, National Testing Laboratories
The most common tannin filters are anion exchangers regenerated with salt.Tannins are large organic molecules with acid groups. The anion resin picks them up both by ion exchange (as acids) and adsorption. They should be regenerated every two or three days with eight to 10 lbs. of salt per cu.ft. Check with your vendor for a proper selection. Sometimes these can be added to an existing softener at minimal cost.
C. F. Chubb Michaud, C.E., CWS-VI, Systematic, Inc.
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