The question was does anyone know a source for bulk pond dyes, you answered:
"very low demand for large containers of dye (even by commercial guys) and the fact that most 5-gal plastic pails cost more than 5 x 1-gal jugs renders the large-package dye-market fairly scarce"
I was merely stating a fact, there are such products available in the market place. I know of one golf course buying drums of the products. I also know of a few applicators using the most concentrated dye available without any problems. With the high cost of shipping these days many cost conscience consumers don't want to pay to ship water across the country. I agree dyes can be messy, but with proper care(safety glasses, latex gloves) and a good dye hand cleaner very little problems may occur. Please note that these dyes have no affinity for cotton and should come out in the wash, especially with a little chlorine bleach. Also note that the blue dye is the same dye used for spray marker to delineate where a pesticide or herbacide has been sprayed and will disapate on exposure to sunlight.