I suggest you allow the jar test to proceed for a few more days to see if the brown is caused by ultra small particles that settle extremely slowly. Also we have to consider a build up of tannin or stain (typically brown) from build up of organics that leach brown tannins into the pond. Some ponds & and lakes have perpetually various shades of light to dark brown from various amounts of tannins depending on the type & amount of deposited of organics.

As an algae expert, I know it is very possible to have an algae bloom any day of the year - even under the ice, certain species of cold water adapted algae can form blooms. Often the blooms under ice are not noticed and do not cause problems - depending on the bloom species.

Last edited by Bill Cody; 12/26/16 01:25 PM.

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