I have small pond full of bullheads that I'd like to kill off. I've been advised that raising the PH to 11, by adding hydrated lime would be a good plan of action. Can someone give me a rough starting point of amount of material needed per acre foot or something? I'm trying to find a source of the lime and before calling anyone would like to know if I need pounds or tons.

Hydrated lime applications can kill fish at rates in excess of 50 pounds per surface acre.
http://pubs.ext.vt.edu/420/420-254/420-254.html

Sounds like a place to start.

Bullheads are notoriously hard to kill. I would rent a trash pump to draw down the water and then treat using an application at the higher end of the treatment range

And the treatment range is?

Might start looking for hydrated lime at a local farmers COOP. If they don't have it, they may know who does. Our local COOP carries a pelleted hydrated lime. I don't know if that would work or not, but suspect there would be no difference once dissolved.

Garden centers might also have it.

< 60 kgs/ha Ca(OH) 2 Slaked lime Hydrated lime Builders lime < 60 kgs/ha CaO Quicklime Burnt lime > 10 tons/ha CaCO 3 , Lime Type Types of limes and recommended rates of application for aquaculture ponds (Wing et al., 2004)

http://wildlife.tamu.edu/files/2010/04/6_Calculating_Treatments.pdf (Cliff Notes - drain pond, apply 1,500 to 2,000 pounds per acre of pond bottom. Pond should be drained before lime is added. Lime should be spread evenly across the pond bottom and allowed to react with the mud. Duration of treatment - 2 days or longer.)

FWIW-I can't help on the amounts Bullhead but I did exactly the same exercise you are doing now, last year. For my 1/4' pond it was hundreds of pounds of hydr lime and I had no way to ensure I got the PH high enough for long enough. Too much work and guessing for me. Instead I got my RUP license online and bought 1 gallon of Rotenone, drew my pond down, and killed every thing with fins.