Pond Boss Forums MANAGING AN EXISTING POND Fertilization factors that predict how long a bloom lasts?

Hi,
My pond has a bloom for the first time! I've watched the last 3 springs to see if a natural bloom would occur. I have not fertilized but there is most likely run off from my yard into it. Last week things must have just lined up correctly. I usually have an early spring slow release lawn fertilizer applied and then the 2nd application in mid June is a pre-emergent crab grass preventer type application. This year however we have lots of bare spots we wanted to seed by hand in the lawn (many thanks to dog pee...) So we asked if they could just do a standard fertilizer. The crew that handles this thought they would instead just put down a starter fertilizer on the whole lawn, partly to help the new seeded areas. I imagine it probably is cheap for them too.

So they came out and put it on and the next night we had huge 'cloudburst' with water running off in all directions. We had washouts and landscape mulch floating into the lawn. I can only assume that much of the fertilizer ended up in the pond. The pond also came up a foot. A second rain event like the first happened later last week. We were away from home but when we came home the water was completely green. A very nice bloom!

Hopefully this is good timing as there are clouds of minnows, populations of ghost shrimp and Gammarus scuds trying to expand their numbers and I have to believe the food chain will be propped up by the bloom.

So I'm curious, what are the factors that affect how long the bloom lasts? Aeration? If I add water from my well to keep the water level at full pool in the next week or so will that 'dilute' the bloom? Do the algae or microscopic critters that make the bloom, also consume the 'resources' and the bloom disappears? I imagine a bloom can be too green, too intense or last too long? Finally, I assume the bloom acts like a pond dye and blocks sun from getting to underwater plants or does sun still get through?

Fish didn't seem to mind, they were so happy that I was home to feed them after a week of no nightly fish food that they were eagerly jumping over themselves to get to the pellets.

My boy got a chinese knockoff of a GoPro and was having fun trying to take underwater pictures. He dipped it in the pond and all he could see was a 'sea of green'

He was curious how long it would stay green, thus the questions today

It depends and varies a lot. Watch you visibility and that will tell you what the bloom is doing. They can last a week or an entire summer.

I have had pretty good blooms the past couple years coming and going all summer. I do aerate, mainly night hours, and we do get runoff from the farmed fields in our area. But this year it has pretty much been a whole bunch of FA which meant raking and more raking. My question is what determines how the nutrients in the pond are utilized?? I have done nothing different but why would one year I get blooms and the next FA?? Much prefer the blooms if I could regulate ....

Light , temps and nutrients are the key to all plant growth. If you can cut off or reduce light penetration to the bottom (where FA starts growing in cooler periods than plankton blooms) you can help reduce FA and encourage plankton.