[jmystro]

First thing to do is find out about where the pH and EC/PPM buffer of the soil is with a quick run off test using RO/distilled water. RO has no pH or mineral buffer. The run off will give a little more accurate result. A decent test is to use about an equal volume of water to media and then check the run off numbers. If pH and/or PPM are out of range, adjust from there. A very high PPM may call for a flush. A heavy rinse will wash out the non metals nitrate, phosphate, sulfate, chloride and molybdate so don’t go heavy mid run without replacing these elements right after a flush.