Question
QUESTION: I have a freshwater goldfish pond.  7 years.  Always ( I mean always) has been  CRYSTAL clear.  Two filters.  Clean weekly. Live in Central Florida.  

Two berry producing trees overhead.  Podocarpus and Southern Red Cedar. Trees have always been here.

I have been to pond stores, and scoured the internet.    

Water milky.  Have drained pond ( 4 weeks ago) and refilled it.  Have used clarifier for the first time... NOTHING.  Have tried algae destroyer... NOTHING.  Water tests normal.  

Poured concrete pond, professionally constructed and sealed, no cracks or leaks, approx 1000 gallons.  Fish appear very healthy.

No change in food, no change in anything, actually!  But now the water is milky... clear in a glass or container, but 1000 gallons are milky  HELP!

ANSWER: The usual cause is a buildup of either sediment or nitric compounds, such as Ammonia.  Test for Ammonia, pH, and alkalinity.  Ammonia should be close to zero ppm, pH at 7, and alkalinity between 3-6 ppm.  If everything seems fine, it is probably sediment.  Perform a 25% water change and make sure to de-chlorinate if necessary.  Use a flocculant to allow your filter pads to better catch the particles.  Also, it helps to use a finer-woven filter pad and hose it off twice a day until the water clears.

---------- FOLLOW-UP ----------

QUESTION: The water tested perfect today (took samples to two places to be sure). Both places said my water is healthy!

I changed about 90% of the water about 4 weeks ago when the problem started and cleaned the pond out ( I mean clean... leaves, sediment, etc.)

I also added a layer of activated carbon ( enmeshed in fine nylon) over the existing filter.  I have been cleaning the filters regularly.  It is difficult to do twice daily due to lack of daylight and work.

Do you think it could have anything to do with the decaying berries from the trees above? This has been a "mast" year for many fruit/berry producing trees...

Thank you so much,

Ann

Answer
It is possible that the berries are to blame, but it would show in the water chemistry.  In just about any case, the flocculant is needed to clear the water.  Did the people just say that it was fine, or did they elaborate?  Sometimes employees who don't know how to properly explain water chemistry will slough off tests results as fine to get out of starting a discussion they are unfamiliar with.  Completely cleaning the pond usually kills off the bacteria responsible for processing ammonia, and results in Ammonia buildup, and sometimes what is described as cloudy white water.