Question
Hi Robyn! My 150 gallon pond has a white foam at the base of the water fall and around the edges. What could this be? The gold fish won't eat floating food so I feed them sinking shrimp pellets, but I remove the uneaten pellets daily. I also had a healthy looking gold fish die last week. Any info/advice you can give me would be appreciated.

Answer
That is DOC - dissolved organic carbons.  It comes from things such as the oils in fish food (some brands are worse than others), the oils on the fish, spawn (fish or frog or toad eggs and sperm), and so on.  I suggest doing a 30% water change.  Add dechlorinator and some pond salt.  Put fresh activated carbon in the filter to help remove the DOC.  Good luck!

Robyn
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