Advice for Koi Pond
I’m wondering if anyone has experience with keeping a koi pond clear of algae? We have tried various chemicals to no avail. We are considering algae eating snails but are concerned they will overpopulate.
We do not have a specialist here for aquatic gardening but we can point you towards more information. There is more than one kind of algae, and some are beneficial. This page from Penn State Extension will help you determine what you have and how to best manage: https://extension.psu.edu/water/pond-management
The chemicals often don't work for long because unless the underlying conditions are corrected- for instance, the water not being shaded enough, how much decomposing plant material is in the pond, or the imbalance of nutrients within in the water. Depending on how large the pond is and if you have a well near where it is located, you could help flush out the water by running the hose into it for a time.
Take a look at these pages from other Extension sites: https://impact.extension.org/search/
And finally, Lilipons is a watergarden info hub and store located in Maryland. You may find helpful information there: