Pond filter: how is sand/gravel?
Has anyone built a sand and gravel filter for their koi/goldfish pond?
- pond is 5' x 10' x 1' to 2' deep
- about 20 koi/goldfish from 1" to 8",
about 100 guppies (increasing by the minute!)
- fed with commercial koi food twice daily, some
nice yummy earthworms whenever I dig 'em up
- variety of plantings: water lilies; submerged
(Elodea/Anacharis, Ceratophyllum, Cabomba);
emgergents: Iris, Typha, Lizard Tail, Thalia, etc.
Water hyacinth floating
- all plants except floaters, submergeds in plastic
pots with gravel layer on top to decrease turbidity
from soil substrate
- submerged centrifugal pump: 1,200 gallons/hour
- homemade submerged filter, about 1 cubic foot
- filter medium is 3 different kinds of plastic
sponge-like foam sheets of varying densities
- filamentous green algae is prevalent but not problematic
The plants are thriving, the fish are gorgeous, the water
it takes several hours and much scrubbing once or twice a
week to clean the crud out of the filtration media.
I realize that this could be alleviated with a larger filter
but the messy and tedious task of rinsing the foam pads
To devise an above-ground mechanical filter that's much easier
One idea: construct a sand and gravel filter similar in concept
to those used in older swi