Saw an ad for used
Billboard Vinyl that got me thinking one of these might block the sun much like pond dye.
Not sure if I would attempt to float it with PVC pipes or some other scheme or just say fuggedaboutit and go with pond dye.
I think both would reduce macrophyte and phytoplankton growth. Essentially one is enforcing a limitations. There are other possible limitations you could force. For example, ph. Or sequestration, (Alum). It may be if you knew the extant that Alum would reduce your ph without adversely affecting the fish you could use a reduced amount of it and save on lime. Usually, however, people use it in combination with lime.
Given the choice of pond dye or floating vinyl ... I think I would opt for the dye. Disrupting atmospheric interaction with the pond surface might not be conducive to the best water quality.
Soils can have a substantial amount of organics (can exceed 1 ton/acre dry weight). Usually only a fraction of this gets recycled annually feeding growth of phytoplankton and macrophytes. As odd as this sounds, it may be better to have the vinyl on bottom to restrict recycling of existing soil nutrient. This may be enough to prevent rooted macrophytes that do not have the ability to pierce the vinyl (some probably do). It probably wouldn't help as much as dye for something like FA.
