It all depends on the situation. We had one pond that had a leak through a sand in the pond bottom. Not a serious leak but more than we wanted. So we added the stuff dry over the spot area. It sank and moved toward the pull of the leak and formed a seal by mixing into the sand. We have also mixed it in 5 gal. buckets and poured it into the pond bottom area by using an 8in. PVC pipe with the outlet about 1 ft. off the bottom.