Pond Boss Forums MANAGING AN EXISTING POND Fertilization What type of fertilzer?

Fertilizers are similar to chocolate cakes. They all look somewhat alike and contain similar ingredients - but they certainly don't taste the same (don't mention this analogy to my wife).
Phosphorus is the driving force behind a pond fertilization program. However, a relatively small amount of nitrogen seems to kick the phytoplankton into gear.
Also, phosphorus is derived from different sources. Mono-ammonium phosphate is the most readily available form of phosphorus, while the phosphorus used in most liquid fertilizers may takes days or weeks to become "available" to plankton - sometimes prompting one to over-fertilize when the plankton doesn't appear to respond to an earlier treatment.
In short, don't over-fertilize - unless you enjoy the prospect of blue-green algae on the surface and a high probability of a D.O. crash when the blue-greens crater.