Melany i went to a Rona recently opened in my neighborhood and saw the product you're talking about. As you said the label lists the ingredient as sodium hydroxide only. But i noticed there is a phone # to reach the company. If you still have doubts give them a call. I don't know which Rona has the right price but yours sure is cheaper!. The 1 KG plastic can was 8.96$ at my Rona. Maybe it's time to stock up