Hi from Eastern Washington

[Elpidia]

Hello, I inherited a pond from the previous homeowner. The pond was large, about 1200 gallons and after 5 years, we downsized to about 600 gallons due to a tragic accident algae control chemical overdose that killed all 120 Koi I had in the pond. I cried. The following year, after cleaning the pond very well and downsizing, I purchased 14 new beautiful koi. 3 did survive, but 6 years later, the rest are still around and thriving. My koi are the one of the joys of my life. Although I yet to learn about how to control the annoying algae 100%, makes the water look like pea soup, I am very very careful with avoid chemicals if at all possible.

 

[MrB]

Welcome to the club Elpidia. I'm so very sorry for the loss of all your Koi friends. Yeah, algae is a real tough one and I am quite familiar with pea soup. Unfortunately, no matter what you do you're always going to have some algae but... You do have a really good non-chemical option. Here's how it works. Algae needs nutrients and lots of sunlight to grow so the idea is to crowd algae out with other plants. So you put lots of "Beautiful" plants in there and they eat up all the nutrients, while blocking out some of the sunlight (With their pretty leaves and flowers.) and the algae is starved out and reduced to a minimum. More plants equals less algae. If you still have too much algae, then you just add more beautiful plants. Win-win.
Hope this helps.

 

[JRS]

Welcome Elpidia. You can make out the green water I used to have to the left in my avatar photo. Added a small bog filter with cattails to my system and no more issues.

 

[Mmathis]

You have excessive algae most likely because your pond is overstocked — the minimum size for one koi is around 1000 gallons, and an additional 250 or so gallons for each addition koi. Koi produce a LOT of waste material that is toxic to fish, but algae thrives on it! You might consider keeping fewer koi. But be sure you have a good functioning biofilter. Also, you might want to get a water test kit and periodically check your ammonia, nitrite, nitrate, and Ph levels.

 

[addy1]

Welcome to the forum!