John:

I do not know what might be in the creek water, but this would be an interesting experiment:

use 5 five gallon buckets and fill each with 4 gallons of pond water
save one as control, then add/mix in 1/4,1/2, 3/4, and 1 gallon of creek water to the other buckets and see what happens. maybe toss a penny in the bottom to see if you can see it. See if any or all floc, and then see if it will re-floc if stirred up again. If nothing happens it may have to be re-done with more creek water. If nothing happens still perhaps it wasn't the creek water after all.

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