The black Stuff came from the pond supply store. I don't think you usually can get it at the big box stores or hardwares.
If you get the Stuff on you, let it sit there and dry. It will peel off completely. But if you try to rub it off right away without using a paint remover, (whatever the can says to remove it) it leaves a very thin coat that just doesn't want to come off. I looked for the can to see what takes it off and it's too far to the bottom of our trash bucket to reach.
It cuts away and even pulls away from the stone where the excess is but I was afraid to pull much for fear of pulling it out of wherever the leak is. I'm going to pull away the Stuff that is up higher on the rocks and leave the rest to just gunk up with normal algae. If I would have followed through on what I intended to do, I would have put sand, pebbles and stones into the wet Stuff to try to make it look more natural. I forgot to get the sand and pebbles before I climbed out on the waterfall and didn't think of it until I was well into the project. Then I was too lazy to climb out and by that time what I had done would have been scabbed over already.
I won't know if it did the trick until later on today. I was having to top off my pond twice a day the leak was so bad. So I'd guess I was losing 5-6" a day. The float was shutting down the pump so I didn't worry about burning up my pump. If this doesn't do the trick then I'm in a bad way because all the rocks and slate is either cemented together or now Stuffed together. It will be a royal mess to redo. Probably wait until next spring if we have to redo it.
It isn't enough that the waterfall is giving us fits. The top of our septic tank is caving in. The installation guy was here and inspected it and said there's no fixing it so that means, "Hello, credit line. $4000 please." Fortunately we have a couple of choices for placement on the lot. We've already moved the drain field because a tree decided the tiles were a great place to get water and nourishment.
