Stationery; ink for writing instruments; ink cartridges for writing instruments; ink sticks; writing instruments; pens; marking pens; highlighting markers; brush pens; writing brushes; fountain pens; ball point pens; mechanical pencils; felt-tip pens; chalks; glitter pens for stationery purposes; penholders; pen nibs; pen and pencil holders; stationery cases

APPARATUS FOR CONTROLLING SOLIDS CONCENTRATION, MAKE-UP WATER, BASIN WATER LEVEL AND RATE OF CHEMICAL FEED IN INDUSTRIAL WATER TREATING SYSTEMS