dying algae

[Steve Nguyen]

not sure if there should be a concern but the algae in my pond are dying off. the pond used to have a thick blanket of green algae but now it's about 90% dead. I think it started to die off about 2 or 3 weeks ago. the fish seems to be doing fine. any idea?

Steve

[luke frisbee]

temperature...many algaes are temperature sensitive

then again daylight started becoming less about a month ago to...

[Steve Nguyen]

I added clay to the pond recently. would it cause the algae to die?

Steve

[MikeM]

Clay should not cause an algae die-off, unless contaminated with something pretty strong. It takes a good bit of even an algaecide to kill it off.

Last Spring I had a period of a couple of weeks when the slimy sort of green algae died off, leaving bare patches. The filamentous algae was unaffected. I think it was just a seasonal change. A friend's new pond developed a dark, almost black algae after it went operational. Then, after a couple of months, it flaked off. Like Luke said, it could be any number of environmental factors. In another couple of weeks I expect you will see algae colonies all over the pond walls, and probably a different type than what you had die off..... Let us know what happens.

[B.Scott]

Steve,
Have you added/changed anything in the pond since the spring?

B.Scott

[Steve Nguyen]

B.Scott,

I didn't add anything to the pond other than koi foods. maintenance routines are the same as previous years. Hope Luke is right on the temperature sensitive. this is just really odd.

Steve

Quote: Originally Posted by B.Scott Steve, Have you added/changed anything in the pond since the spring? B.Scott

[koiczar]

Steve

I believe it is seasonal. I had mine die off only on the bottom last year and this year is about the same. It's been that way for the last few weeks. The walls are mostly unaffected however.

Mike

[EmeraldKoi]

If your pond filtration has stabilised and the fish are not eating as much as usual due to the lower temps, there will be less amonia, less nitrite and nitrate and thus less nutrition for the algae. It could be starving off naturally, and this is a good sign for the state of your filtration. It is cyclical as when there is no algae, the nitrate rises, and the algae starts growing. It replicates fast, up to a blanket stage, and at that point will be consuming more nitrate than the fish and the filter produce. Suddenly, the nitrate is all consumed and the algae will go from green to brown, and then die off a week or so later. Then the nitrate builds up again and the cycle continues. Check the nitrate, if it is low or nil , you have the answer. I find it is not something to get concerned about. Fish love green water and hobbyists love clear water. Win-win situation either way! I bet in a month the algae starts up again.