Green water, murky water, clear water, got a pond or fish problem....?
CHECK YOUR WATER QUALITY! Sorry for yelling, I'm just a frustrated KHA

Green water means you have a water quality problem.

Not necessarily a problem for koi always... could just be higher
phosphates alone. jay

Perhaps, but people need to check to know it's not because the pH is out of
whack, the buffering(KH) is gone, the nitrate is overly high, and/or
ammonia & nitrite are in the toxic range. All those readings excellent,
then we go back to patience or, for the less patient, UV. ;o) ~ jan


(Do you know where your water quality is?)