Is there an issue with using Merck DIPA bottles instead of Hach DIPA bottles?
9240 and 9245 Sodium Analyser and Bottles
The Hach bottles have an O-ring at the mouth of the bottle while the Merck bottles do not have this O-ring? There is no problem or danger to use the DIP A bottle without the white collar on the top of the bottle. The isolation is made by the O-ring located on the top connector where it is also connected to the porous cartridge. That's more than sufficient to assure appropriate tightness. The vent should be free of blockage if you want the conditioning Venturi effect working.