comments:
Dr_Wigglespank posted on r/aquariums1w
I have a small tube of silicone faucet grease I picked up on Amazon (link). Most hardware stores should carry it, as well.
Tim_E2 posted on r/plumbing1w
Get this: https://www.amazon.com/Danco-80360-Waterproof-Faucet-Grease/dp/B000DZFUNY Look for NSF-certified food grade silicone grease. Replace the Big Blue O-ring as needed.. every filter change or two for cheap O-rings, while good ones might go 5-6 filter changes.