Macherey-Nagel have a selection of VISOCOLOR Powder Pillows available for free Chlorine, total Chlorine and pH photometric determination. [caption id="attachment_13713" align="aligncenter" width="224"] Free Chlorine VISOCOLOR Powder Pillows[/caption] The benefits of VISOCOLOR Powder Pillow includes: Long shelf life- 5 years from production Easy dosing- all reagents in just one powde...