Fertilizer serves two purposes, when applied and managed correctly. First, a healthy plankton bloom is a balanced mix of phytoplankton and zooplankton. Nutrients dissolved in the water column feed phytoplankton, which is natural food for zooplankton, which feeds the tiniest insects, which feed bigger insects, which feed newly hatched fish, and so on. Purpose one is to ultimately feed newly hatched fish. Think about those babies. When they are first hatched, the only food they have is what they derive from the yolk of their egg. Once that's absorbed, these young fish have no energy stores. They haven't eaten anything, therefore they have no body fat. They must eat now, and often, or many of them starve, quickly. Plankton is the fundamental source of food, at the very base of the food chain. Job one of fertilizer is to feed baby fish. The second role is to shade the water, to prevent excessive aquatic plant growth. When visibility decreases, the area which plant growth can occur is diminished.
While people often understand the value of fertilizer, the 'problem' occurs because they don't completely understand how to do it, and how to maintain a bloom. Realtors base value on three things, location, location, location. Fisheries managers focus on 'timing, timing, timing.' Miss the timing, and bad things happen. Fertilize too early, and you get no results. Water's too cool. Wait too long, and you feed plants.Fertilize too much and you run the risk of oxygen depletion. Fertilization is a simple concept, as long a the pond manager understands how to play the game.
Dye works in a simple way, too. It blocks a certain spectrum of the sun's rays, basically to prevent rooted aquatic plant growth from the bottom of the pond. While the concept makes sense, dye also inhibits phytoplankton growth at all levels. When the water is Tidy-Bowl Man blue, phytoplankton can't grow. Zooplankton can, but since they eat phytoplankton, their growth and quantities are limited. As the dye deteriorates in direct sunlight, water takes on a shade of bluish green, the greenish blue, then green....and so on. That's when phytoplankton begin to do what they do, once they can get required sunlight penetration.
In ponds that are not heavily fed, where the manager depends on the natural chain of events, a healthy fertilization program grows four to five times the numbers and pounds of baby fish than clear water.
I, too, have fertilized ponds and been rewarded with plant growth. But, it wasn't the fertilizer's fault. It was mine, because I missed the timing window, or didn't maintain the bloom.
Properly managed, fertile ponds will outproduce dyed ponds four to one with fish, in a natural setting.
Fish producers typically fertilize, followed with an intense feeding program. But, they always have a source of fresh water, fast, in case they mess up.
I use fertilizer often, with great results.
I tend to stay away from dye, unless the pond sits in an urban setting.
There's a big project in upstate NY where I spend lots of time. Fifty hatchery ponds adorn this private wildlife preserve. We are able to successfully fertilized about forty of those ponds. The others simply won't take a bloom, probably because of too much shallow water, or too much flow through. The fertile ponds outproduce all the others. About fifteen ponds are used for fathead minnow production, to supply fish for larger game fish production ponds. Those fathead ponds produce a huge amount of fish, due to the manageable levels of plankton. We stopped raising small fish in ponds which tend to vegetate and won't hold a bloom. That's where we grow tiger musky, larger largemouth bass on feed, advanced walleye and smallmouth bass on feed.
So, fertilizer is like many of the tools of the trade. Learn how to do it properly, and your pond is built with not much shallow water, and fertilizer is your friend. But, miss the timing window, and expect to be frustrated.
