i recently did my first attempt at homemade concrete mix rock, using some tips that i read about. have to admit, came out pretty o.k., except the dull gray just didn't do much for me. so i had an idea of dripping some food coloring on it,letting it dry, and then soaking. it really looks great, as the colors softened and muted a bit. was wondering if this would be safe for fowr tank. currently soaking in salt water, probably for another week or so.
