Epoxy resins come in “block” form. The distributer cuts it down and mixes it with water before packaging it – making it into a liquid form. That is where the “water” came from. Manufacturing of the resin/epoxy raw material is a very complex process. Requires very expensive equipment, and high level of manufacturing expertise. I go back to my original premise: Pond Armor with 2 guys in southern California, are not manufacturing their product. You can argue what defines a manufacturer, but clearly if you are not making the raw material you are NOT the manufacturer.
I am not saying anything negative about Epoxy/Resins in general, just that you should think twice about buying material from some fly by night company, rather than an established organization that stands behind their product.
Also, if you read their literature on their site, there is very little mention of using airless sprayers. Even the picture on the home page shows some guy using a roller to apply this stuff. Here is a link to their Applying Pond Shield link:
Pond Armor - Non Toxic Epoxy and Polyurea Pond Liners and Sealers
You can argue for a long time about what the best method is, and how much of an expert you are in building ponds, the bottom line is that Pond Armor is over priced, and is not well supported by the company. Also, can you tell me that these 2 guys will be around in 3-4 years when this stuff starts to peel? I think we can all agree that a company like Nelsonite and Xypex (thanks Luke) will be around. Pond Armor is pretty much a fly by night endeavor.