I’m just happy it doesn’t leak, or I didn’t drop a 20 pound slab of limestone in it when I was cleaning it out for refill… it hasn’t had water in it for 20 years… so far all have been leak free… they all evaporated dry when I quit fish about 20 years ago this is my new background, and new black sand, and a piece of wood soaking up water… I may add this piece to my Tilapia tanks, as I have a nice piece in my Asian tank, and it’s too crowded to insert Repashi sticks, without knocking something else over….