Thanks for all the advise gentlemen. I havent done a real application of the alum yet I just now got the hydrated lime. In the post that you've recomended and sugested yourselves pre mixing the alum into a slurry is the best way then spraying it. I'm trying to come up with the best way to do that. Has anyone ever tried a texter gun for sheet-rock for blasting the alum into their ponds? lol
If you just have a sack or 2 to apply, that could work pretty good.
However, I have repeatedly applied alum by just dumping it in a barren corner of the pond. It completely dissolves and disappears within 2 hours, and resulted in zero fish kills. I found that it dissolves at the same rate as table salt. A teaspoon of either poured in a pile in 1 corner of a shallow pan of water dissolves in about 1 hour. The alum taste is just as strong in the far corner as in the corner where it was piled up, just as salt would do. That's because alum is chemically very active, and diffuses very quickly. You may remember the skunk odor diffusion experiment in school. You uncork some skunk scent in the corner of a large room, and it travels 50' in less than 5 seconds with no wind to aid dispersal. Within 30 seconds, the skunk odor is equal in all corners of the room because of molecular diffusion.
Hydrated lime is a lot different. The particles are large, and do not readily dissolve. Mixing and stirring it helps to dissolve it a little faster, spreading it widely helps it dissolve even faster, but exposes the fish to more of it. So there's no perfect way to apply it.
Whether or not you mix the lime, most of it quickly sinks to the bottom, making a thin white layer. This layer of hydrated lime takes days to weeks to completely dissolve, depending on how hard or soft your pond water is,,, and of course how thin the layer of lime sediment is. Ideally, you should spray a little lime stirred up in a lot of water, and broadcast it widely in barren areas. Realistically, that's very hard to do. I wound up spreading several sacks of it with a 5gal bucket, just tossing it dry in a barren area of my pond to avoid fish stress. I had 1 floating small BG, so it was very acceptable. After 6-8 weeks, there are still a few streaks of lime visible on the bottom, but in my experience it will eventually dissolve.
