Fish produce ammonia through their gills and other waste. Ammonia is toxic.
Bacteria convert the ammonia to nitrIte. Nitirite is toxic. Bacteria
convert nitrIte to nitrAte. NitrAte is fertilizer. If you don't have
enough plants to use up all the fertilizer, then algae does the job for you.
The bacteria form on all surfaces in what is called a biofilm. The biofilm
covers the pond, the plumbing, plant roots, and filter media. With a sand
filter, the biofilm builds up on the sand grains and clogs the filter such
that you are running very high pressures indicating a need to backwash. The
biofilm is stubborn to wash off, and you don't want it to be washed off.
Therefore sand is a poor filter material. Find a material that is smooth
and will barely sink to make backwashing easier and the filter run better.
The bead filters are sand filters that have the water run through in an up
flow method with floating plastic beads, but there are plastic bead media
that are heavy enough to settle, and these should be used in the standard
downflow mode of a sand filter. The beads should all be the same size to
accommodate water flow without clogging.

Start with testing of the water to see if the filter is working to get rid
of ammonia and nitrites since these can kill fish.

Once the filter has been converted, a lower energy pump, like a Sequence,
should be adequate, and will save you mega bucks in electricity.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html
"matt clark" wrote in message
om...
Hello to all ponding experts. I would appreciate a few of you taking
the time to post a reply to the following question. I am in dire need
of help.

My setup consists of a 2200 gallon concrete lined pond with a hayward
1.5 hp pool pump which pumps at about 90 gpm and it has a filter
basket, and a hayward s180t sand filter, which has a flow rate of
about 35 gpm. My pond has a water fall and a bottom drain. When i
first filled the pond everything was good for about 3 months, then it
started getting green. The initial media for the filter was silica
sand. But after a few months i had to backwash everyother day. So then
i switched to lava rocks. They worked ok for about a month and then
started clogging up just as fast as the sand. I have some plants in
the pond, but the sand filter is about the only filter i have on the
system. I wouldnt mind flushing the filter if at least the water
stayed clear. I live in Tucson AZ, where it gets pretty hot and sunny.
My backyard is new so i dont have a lot of shade. i planted trees, but
they just dont seem to grow fats enough. I had a total of 4 koi to
start with, but 2 have died off, and im pretty sure it has something
to do with the green water. I am looking to find a home for these 2
fish if anyone in the tucson area is interested. ohh yes, also my
electricity bills are way too high because of running the pool pump
24/7.
So with all of my pond problems listed, i would greatly
appreciate some help. I have been looking to buy a moderate priced
filter and pump system, or maybe build one myself. If anyone has any
ideas on how to modify my current setup, or media types for the filter
i could use all the help i can get. Or if anyone has suggestions as
for what to but to fix my problem. I also forgot to mention that i did
try the liquid pond cleaner bacteria and had no luck.

I really will appreciate any advice. Thanks for the help in advance.

Matt Clark