Pond Boss Forums MANAGING AN EXISTING POND Fertilization Fertilized first time - excessive bloom?

I have a 0.4 acre pond. It has a plastic liner and is fed by a well. It was just filled a little over a month ago.

I ordered some Perfect Pond Plus 12-48-8 and it recommended 5 lbs per acre. I weighed out 2 lbs of the fertilizer which amounted to two red solo cups full. My son and I spread this out over the pond on June 28th - 8 days ago.

I was out of town from the 29th until the 3rd and when I came back the water is a dark green. Previously it was so clear you stand a little over waist deep and see your feet. Now you can't even see your hand 6" under water. I have ordered a Secchi disk and am reading up on the 12-18" desired visibility.

I have also noticed the bubbles coming up from my aerators are now foamy looking. Prior to the the fertilizer and bloom they were not like this.

No dead fish or strange signs and they seem to be feeding like normal but this was such a drastic change I hope everything is alright.

Attached are a couple pictures.

Why did you fertilize? What were the goals? Couldn't you have just fed the fish to make them grow in the clearer water?

I was reading that fertilizing a pond can increase fish production by 3-4 times by stimulating the growth of the microscopic organisms which are the base of the food chain. I also read that the phytoplankton produces oxygen for the fish - both of which seemed like good things.

While I am feeding the fish daily with small pellets they are still likely too big for the tiny fish.

In all the previous threads I have read through on the subject I did not find any saying it was a bad idea to fertilize. They all seemed to say it was a good thing?

All pond management practices have pros and cons. Many things can be promoted positively and some of the negative features ignored or not realized. It takes unbiased, in-depth knowledge and often extensive experience including mistakes to fully realize the many pros and cons of the options for ponds.
What you say is true: ..."fertilizing a pond can increase fish production by 3-4 times by stimulating the growth of the microscopic organisms which are the base of the food chain. I also read that the phytoplankton produces oxygen for the fish - both of which seemed like good things."

There is such a thing as too much of a good thing. The other side of fertilizing is that improper nutrient balance of fertilizing can produce too many good algae, harmful toxin producing algae (Cyanobacteria), and nuisance algae.

An improper nutrient balance can occur in a good fertilization application as the algae selectively use too much of one nutrient which promotes growth of another specie or group of algae who require a different nutrient balance. Not all phytoplankton are the same specie nor do they all require the same amount of nutrients to thrive. When one fertilizes,,, the nutrient nutrient concentrations should be monitored regularly in some way so the correct nutrient balance and correct algae species and numbers are maintained. Few do this, and often or eventually they end up with some sort of algae problems.

Proper fertilization is tricky business. Tricky in that fertilizer needs to be added timely so the wrong type of plants do not grow. The older a pond becomes the more types or species of plants that become established. Thus in later years when fertilizer is added it can cause nuisance new plant growth instead of good plankton growth. Fertilizing now feeds the new colonizer, immigrant, or invader.

Too much fertilizer will cause too many phytoplankton, make the water visibility too low and then a real danger of a fish kill looms. Phytoplankton do produce oxygen, but ONLY when they receive adequate sunlight. During night these same phytoplankton use or consume oxygen, thus what they produced can be reabsorbed at night. When there isn't enough excess oxygen to last all night a dissolved oxygen (DO) shortage occurs - too many oxygen "breathers" at night. Whenever the DO is marginal or low in the morning and the day or next days are cloudy - rainy, (sunlight minimal), not enough DO is made during day and not enough surplus DO going into night and DO becomes too low by morning. Fish kill aka summer fish kill.

Fertilizing adds excess nutrients to a pond. Ponds age and become eutrophic and then later over-enriched (hyper-eutrophic) buy collecting or accumulating nutrients as years pass or an excess of fertilizer is added. The more nutrients present, the more plants that grow, and more plants that die, which create more bottom muck. This causes faster pond filling in and moves it quicker toward its end of life as a shallow marshy area. This process is called aquatic succession. IMO fertilizing does increase fish production by 3 or more times but it does also increase the speed of pond aging by at least 3 or more times.

One simple way to reduce or minimize all of the above and still grow more and bigger fish is to feed the fish pellets. This also does enrich the pond with nutrients, however it is less tricky, and generally has fewer inherent problems and more slowly ages the pond than the fertilizing program. Plus it generally allows for clearer water and better quality water compared to a light, moderate, or 'heavy' fertilization program.

One has to remember that pond fertilization was originally developed for well monitored and managed hatchery or grow out shallow ponds. These ponds were regularly drained and allowed to dry out to minimize the aging process and reduce bottom sludge. The fertilization concept was then later adapted to farm ponds and small lakes. The concept of eutrophication, nutrient nuisance and toxic algae growths, and associated problems were at the time not seriously considered as problematic. IMO pond fertilization should be carefully considered in light of today's available environmental information and need or desire for overall water quality.

Thanks for the very detailed reply. It all makes very good sense. It sound like I will be better off without the fertilization. Should I just never do it again or is there some special procedure I should use to wean off from it?

It seems like I could write a book with all the stuff I have learned from here.

You are getting good input from Bill, which boils down to "It depends." Fertilization is good, depending on the situation. But it can be really bad news if the situation isn't right, particularly for already fertile ponds.

I've fertilized, and it did help produce a bloom. It also helped grow chara, which has both good & bad points.

If you have tiny stocked fish, you may wish to feed tiny fish food. Purina and Optimal make several types, including stuff that is more like dust for newly hatched fish. I'm using it now and have noticed that I'm suddenly seeing lots of YOY fish in the shallows.

The best BG fishery in the country, Richmond Mill Lake, has infertile acidic water. No fertilization would work due to water flow. Yet extensive & intelligent feeding has created a paradise for trophy panfish.

Yes fertilization depends on ones goals and ability to manage the pond. Fertilization is recommended more for southern ponds compared to northern ponds for several reasons. I will not explain the reasons here, but I may do it in a Moderator's Corner segment.

You can stop adding fertilizer and the nutrient concentration will gradually be naturally decreased by plants absorbing, growing, multiplying and dying in the pond. This puts most of the nutrients bound as organic material onto the pond bottom. Some of those nutrients went into producing fish and animal biomass that are eventually harvested or die in the pond and are eventually recycled in some form or another. However, most of those nutrients went into plankton that died and sunk to the bottom to accumulate as bottom muck. Often it turns into black bottom muck aka sludge.

Be aware that when you do not fertilize or stop fertilizing and the pond becomes clear with more water visibility the higher 'level' plants (more advanced than phytoplankton) will begin growing, some quickly and thickly, on all bottom areas that receive sunlight. These plants include filamentous algae including Chara/Nitella, periphyton (attached community of numerous species), and many types of rooted plants. To a certain extent these higher plants can benefit the fishery but generally not nearly as much as the fish growing benefit from phytoplankton. These higher plants compete for nutrients and space with phytoplankton.

Stimulated growth of phytoplankton from fertility (natural or added) shades the water that reduces growth of the above named plants that can be a nuisance.

One option to fertilizing, to achieve water shading is use of pond dye to reduce light penetration into the water. Water shading can also come from suspended silt, clay, and detritus. Shading the water with dye or turbidity has light limiting effects, but also reduces the amount of phytoplankton that can grow due to less light entering the water column. Phytoplankton need light to grow. Dye allows for clear water and provides the light shading effects depending on how much dye is used. Dye can also be used as 'make-up on a pig' to enhance the appearance of turbid water.

Hello.

Thank you Mr. Cody.

A+

The archives have info on fertilization which everyone should read before you seriously consider fertilizing. Many ponds do not need added productivity (fertilization).

Cody Note: Here is the link to the Fertilization Thread in the PBoss Archives.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=96127#Post96127