D.O.C..........

DOC

Dissolved Organic Compound

Some of the warning signs that things are getting out of control

a). Foam on the surface
b). Dropping / low ORP.
c). Blanket Weed (string Algae).
d). Constant Nitrite levels.
e). Yellow water.
f). Murky water.
g). Koi appear Sluggish.
h). Smells from the Filters.
i). Falling PH Levels.
J). High Nitrate levels.
k). Climbing TDS levels.

DOC is the after effects of many things going on within the pond and the sign that the water is getting tired..... Leading to some or all of the things you see above.

Prevention methods are:…

a). Water Changes.
b). Filter maintenance.
c). Good Aeration.
d). Protein skimming.
e). Surface Skimmer.