Hi Mike,
I also started started using the Twilight blue dye the past year, and can give my experience with my 1.2 acre pond.
On the first batch one quart was not really enough to get the results I was looking for (less than 24" visibility) so I added another.
The results with two were good for me. To refresh, I've since been alternating between Nature's blue and Twilight blue to get more of a blue tint. Your results may vary, I think the color tint has more to do with the pond minerals present.
