Salt Mass Balance & Corrective Flushing
Root-zone salt as an in/out mass balance, why runoff EC (not feed EC) is the ledger, the corrective-flush protocol for EC creep, the myth of the end-of-crop water-only flush, and how coco's buffer vs rockwool's zero buffer change the math.
The root zone is a bank account for salt
Every problem the coco track blamed on "overwatering" and every slab-EC spike the rockwool track chased is one idea: salt mass balance. Salt enters the root zone dissolved in your feed. Water leaves by transpiration and evaporation — but the salt it carried stays behind. The only way salt leaves is dissolved in runoff. So the root-zone salt load is a running balance: in (feed EC × volume applied) minus out (runoff EC × volume drained). When export lags input, the balance climbs — that is EC creep, and it ends in pH swings and lockout.
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