I have been really interested in getting an air stone for my tank, not for any reason other than the fact that I love the effect they give. However, on reading through the Juwel manual which came with my tank it says that airstones should not be added under any circumstances because it effects the strength of the sealant. I was just wondering if anybody could qualify this as being true or if it is just Juwel covering themselves. Also, how does having an airstone in the tank effect the sealant anyway? thanks 