Ok. My boys are BRATS! They love to destroy All kinds of things. Fences, gates, trees, feeders, hay holders, and water buckets. They can really frustrate me. And dont get me started on their.horns....geez I found for.my boys..if it is sunken. They.dont tear it.up. So I.looked and.found.a.metal pipe with a 1/2 inch lip. I put a cap on the other end. Its about the size of a cup I stick this into the hole of their.spools. yes I usually add to it on a 2 day schedule. But they like licking their own spool. And I dont feel they waste much. Not like they did with.pvc pipe on the wall Yea..I filled it.up 1 time. Lost alot a good mineral!..