Hold times for chloride, EC and pH vary with jurisdiction, ranging from "28 days" to "unlimited when dry" to "unlimited", thus hold time is rarely an issue for these tests.
In most locations, these parameters are routinely run off of dried and ground (DG) samples. Drying and grinding increases ssample stability, thus the unlimited hold time. The exception is Ontario which specifies a 30 day hold time for pH on an "as received" (wet) sample. EC and chloride are umlimited when dried.