Permanent Waterproofing for Flies?

[chemdoc]

I came across a product by Cortland called Watershed waterproofing, which apparently permanently treats flies and avoids repeated use of floatant. I was wondering if anyone uses this type of product and how well it works.

[Adam Grace]

Watershed is not made by Cortland, but it is a pre-treating agent.

I have only used it on a couple of flies, I forgot which flies they were.

Pre-treating waterproofing liquids like Watershed have been around for a while but they haven't really become super popular.