plexiglass cover for pond - taken from inside greenhouse

VEGGIE FILTER - water celery with small pump

MARCH 29TH, 2008  The pond in winter. The box indicates the area where the "in pond filter" hangs and where the water returns. The pond has a single 500 watt heater and plastic to retain heat. The water temp is usually around 50 - 54oF all winter except when outdoor temps plunge below zero (about one month).  I feed 1/4- 1/3 cup freeze dried krill (22 KOI) all winter as long as the KOI swarm up to the surface and beg for food.  I dont feed every day, maybe once a week.  As the pond warms up in spring (and I can get to the pond) I feed more often.

However, in spring the algae turns the pond into pea soup from the excess nutrients.  The regular veggie filter on top of the pond (under the plastic in the picture below) doesnt get up and running until June and all that time the water is pea soup.  For a long time I thought about some kind of veggie filter that would sit IN the pond during winter and slurp up the excess nutrients.  I know water celery is very resistant to frost since it comes up very early in spring and grows unfazed thru late frosts.  I really dont know how cold the air under the plastic ever gets, but the water never gets below 45oF or so and with the return from the pump disturbing the surface there should be adequate warmth in the corner where the filter and heater are.

In fall I had a really packed root mass and a big head of water celery growing out of a 4x4 plastic pot that I put into the garbage can.  I didnt have the can high enough out of the water and the little piggies threw themselves in and ate the top off the celery and chewed up quite a bit of the root ball.  I stuck what remained of the root mass in one pot and took another bit from my basement where I overwinter the cyperus.  It started out with a few puny sprouts in December, but is coming on strong this spring.  Previous experiments indicated growth was related to concentration of wastes.

So far, the water is quite clear of algae altho I cannot remember how pea soupish the water was last year this time.
Corner where the filter, heater and water pump is situated.  The garbage can has holes in the bottom. The celery is barefoot in plastic containers clipped to the side of the garbage can to prevent them from sinking. 
LEFT:  I tried an experiment to see if the growth of water celery was affected by its position in line with where the nutrient laden water entered.  The results were obvious. The water enters from the left and the first plant in line grew largest (5-18).  This disparity disappeared by 6-24. 
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