Keep the two water systems separate
Identify the water used for powder make-down and the water within the process suspension. A recycled source may serve one or both roles, with different consequences for preparation and treatment. Record source, sampling time and measured chemistry for each.
Do not infer complete salt composition from conductivity alone. If specific constituents matter to compatibility, ask for the relevant measured information. Avoid ordering a nonionic grade on a generic promise of resistance to every saline condition.
Screen preparation before comparing treatment
Prepare the proposed powder with the intended make-down water under documented conditions. Look for consistent dispersion and usable stock. If another water is being considered, run a matched preparation comparison instead of changing feed and water at the same time.
The paired water-source test provides the preparation investigation. Keep its result distinct from the purchasing question of which candidate performs acceptably on the actual saline suspension.
Test credible changes in the circuit
Use representative feed and a defined dose basis to compare separation. Where recycled-water conditions vary, collect credible contrasting samples rather than creating an arbitrary laboratory salt challenge and treating it as a plant guarantee.
Record liquid quality and solids behavior together. If a candidate works only under one narrow condition, decide whether additional evidence is needed before relying on it for normal supply. Nonionic is not a promise of universal insensitivity to dissolved salts.
Specify the qualified envelope
Retain the accepted water sources, preparation method, product code and measured endpoints. Ask what supplier review is needed if the water source changes materially. A repeat purchase should not silently expand the original trial conditions.
Include preparation-water demand and expected consumption in the sample and supply enquiry. Check the capacity implications with the make-down demand calculation before committing to bulk supply.
Decision record for the quotation
| Decision | Evidence needed |
|---|---|
| Water roles | Preparation source and process suspension are separately identified. |
| Variation | Samples represent actual circuit changes, with measured values clearly distinguished from assumptions. |
| Purchase envelope | Code, water conditions and acceptance evidence travel with the order. |