According to Fritz website: “The presence or absence of an odor is not a sign of effectiveness and can vary from batch to batch. If it is within shelf life the product should be fine.”
Normally love this product. I always bought the 16oz bottles though. This gallon batch was off though. It's supposed to have an earthy smell to it not rotten eggs. So either it was bad luck or perhaps it wasn't stored properly I dunno.
First time I’ve bought a gallon and it smelled like raw sewage?! Never had that smell come out of the smaller bottles??
Great product! I use it at each water change for all my aquariums, and when adding fish. Highly recommended.