SMC (6850490) 685 Hastelloy Poly Check Valve 1/2" NPT 20 inch x 4.5 inch Big Blue Filters2065 or discoloration—these indicate imminent failure

or discoloration—these indicate imminent failure that could interrupt chemical dosing and compromise water quality

Every 9 Months

and check for leaks around the housing o-ring

More filtration surface area in the same footprint means longer runs between cleanings and better dirt-holding capacity than standard sediment cartridges

SMC (6850490) 685 Hastelloy Poly Check Valve 1/2" NPT 20 inch x 4.5 inch Big Blue Filters2065 or discoloration—these indicate imminent failureSMC Professional Grade SMC 685 Hastelloy Poly Check Valve 1 2" NPT Polypropylene inline check valve with Viton seals and Hastelloy springs for reliable backflow prevention in demanding water treatment applications Model 6850490 125 PSI WOG Chemical Resistant WHY IT WORKS Built for Corrosive Environments Hastelloy Spring Corrosion resistant Hastelloy spring maintains consistent closing force even in aggressive chemical environments where standard