Above is a cross section of my lower pond and the filter, before we removed the island. A is the skimmer using 1.5" tubing, B is a Tetra Bell Vacuum Bottom Drain using 2" tubing, C is a triple camlock fitting where the hoses can easily be attached or disconnected. This fitting connects to 3" ABS and connects to #1 barrel where the water comes in at the bottom and drops the muck there. It passes thru D, 25 yds of vinyl screening held down by hardware cloth. At the top of this filter I grow water hyacinths. Using a screen to keep their roots away from the bulk head fittings into the bio-filters. #2 barrels contains E open cell foam (20 psi) water flows horizontally thru to #3 barrel that contains only the pump, an automatic shut-off float switch (not pictured) and F water.

Maintenance: In my case, I have a fully stocked koi & water garden (1500 gallons) that these filters have kept clear through out the season of March thru November. Only maintenance is cleaning the prefilter once every 6 weeks and this takes about 30-40 minutes.

I break the siphon and cap the bulkheads going to the bio-filter barrels. I then remove the water hyacinths to a bucket, where they will get a rinse & root cleaning. Pull out the vinyl screening to rinse on the lawn, rinsing most of the muck off as I pull it from the barrel. I use an old LG pond pump to remove the dirty water and a shop vac to remove the muck. Then I replace the vinyl screening, refill to the top with water and restart the siphon. This is done easily by using the suckie-uppie device pictured or one can simply use their mouth. :o) I use to use the shop vac on 1-1/2" tubing off the 3rd camlock, not fun but do-able. That camlock is now plugged. For a new pond, I would go thru the liner with bottom drain & skimmer and not have the piping in the pond, or do the siphon effect.

In August I clean one barrel's open cell foam, using a power washer, this takes a minute per pad. They can also be cleaned with a hand-held hose end sprayer, takes 3-4 minutes each. Around the end of October I clean the other bio-filter barrel and plug it and the pump chamber off, and store dry for winter. The pre-filter and the bio-chamber cleaned in August are used for flow during the winter months. I disconnect the bottom drain and plug that connection. Water flows from the skimmer only, into the pre-filter using a small 350 gph pump on the far side of the bio-filter foam. Doing this has really helped my bacterial action start up sooner in the Spring.

I figure I spend 6 to 10 hours total/year on filter maintenance.

Depending on fish & plants I feel this system could filter up to 2,500 gallons, if one increased the bulkhead fittings size to 3" to handle that added flow. It has gotten a good test on a Master Gardener (MG) demonstration pond of 2,000 gallons in full sun. The MG pond was mainly to be a water garden with rosie reds. It ran for 2 summers without one day of suspended algae. In 2002 koi were added, and so far, the filter has continued to perform as intended.

For a smaller pond, 1100 gallons and less, I believe one could remove one bio-chamber, if it wasn't a "koi only" pond. One must take into consideration flow rate, too fast and the bacteria doesn't have time to do it's job, too slow and a no-nitch skimmer design won't work at optimum. For filter design/performance the best website for in-depth research reading is located on the AKCA website under Koi Health Advisor - Pond Construction and Filters.

Lastly, I'd like to add that this filter has been used on many ponds locally, with great results. One pond type it hasn't been used on that I know of, is a plant-less koi only pond. IOWs, YMMV in all things pond related.

Demonstration pond filter - Includes parts and a photo based on the filter above.

Behind this rock is.....	The little brass fitting I connect to a suckie uppie device to remove the air to start the siphon.
Here is a photo of a flower pot filter from Terry in Texas.	Jan Clark's home-made filter ($30) in Vinita, Oklahoma.
Debbie of NY's, homemade pot filter, $11, quilt matting as media.