joining rocks with rods... what type is good?

[Tarolisol]

I belive they have the same stuff at home depot aqua somthing or other, it says it can be used in ponds so i think it would be fish safe. Ive used it in vivariums with frogs and havent had any problems, but im not worried to much about PH in that case. Seems like a good way to make rocks very secure, but be sure you are happy with your aquscaping before applying that stuff.