Total Dissolved Solids

Definition

The combined concentration of all dissolved minerals in boiler water, a key limit for controlling carryover. It rises as cycles of concentration increase.

As cycles climb, TDS rises along with alkalinity and silica, each capped by ASME and ABMA guidelines to prevent foaming and carryover. After pretreatment the remaining solids are mostly soluble sodium salts and treatment chemistry byproducts, far more soluble than the calcium and magnesium removed by the softener. TDS is commonly tracked through conductivity on a cooled sample.

Related concepts

Foaming · Conductivity · Conductivity Controller

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Part of The Blueprint of Water · 📏 measurement