I have a huge snail problem but that has noth'n to do with the metal. nick aSergeantPosts: 113Location: AustexSubject: Re: Is stainless steel safe for an aquarium? 9/1/2010, 3:09 pm Most types of SS are quite stable in water....especially in fresh, higher pH water.Some grades are better than others 316 is better than 304...316L (low carbon) is better than plain 316 etc.......Any pump impeller that