A set of 2 ampoules of solids for dilution up to 2 litres of residue-free water. Vial 1:Filterable residue (TDS). 441 mg/LNon-filterable residue (TSS) . 57.1 mg/LResidue (Total solids) (TS) . 491 mg/LVial 2:Filterable residue (TDS). 250 mg/L Non-filterabl