A K-1766 salt testing kit costs less than $30 and is far more accurate than either your test strips or your SWG reading. You can certainly continue to use the strips but they are not very accurate and they are easily spoiled by humid weather if not kept in a cool, dry place. Only the K-1766 can give you the most reliable and accurate reading because it is based on direct chemical measurement of the chloride ion (Cl-) concentration whereas all other methods (srtrips, meters, etc) use a proxy (conductivity or density differences) to infer the salt content. The K-1766 can perform over 100 tests and the reagents are very stable and will last years. Well worth the investment of $30.