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Overview
We've been building Bio-Mass (Veggie) filters
for quite a number of years now and find them to work exceptionally well in
season,
with a little maintenance. Although our design incorporates a settlement system
for particulate filtration, it may be necessary to add additional particulate
and biological filtration, especially in Koi ponds and in temperate zones where
the cold weather causes plants to go dormant.
Getting
Started
Start with a preformed pond or container
that equals roughly 10% of your main pond gallons i.e. Your pond holds 1000
Gallons you need a 100 gallon preformed pond or container.
Bottom
Drain (s)
You need 3- 2" bulkhead fittings
and a 2 " ball or gate valve with assorted PVC pipe and adapters.
You can use any diameter hose or PVC depending on your configuration. Drill
a hole into the bottom of the pond-install your bulkhead, PVC piping and
drain valve. This drain will allow you to flush the
sediment out of the Bio-Mass filter periodically.
On units larger than 6' x 4' more than 1
bottom drain should be installed.
Bottom flow
chamber
The bottom 6"- 8" should be your
water flow chamber and should not contain any rocks. You can accomplish this by using milk or
bread crates or a grid of PVC piping with hardware cloth or screening to stop
the river rock from falling through. This chamber will allow water to circulate
the entire bottom of the pond feeding the roots evenly. The chamber also acts as
a settlement filter and chamber and helps with flushing
particles out of the filter via the bottom drain
.
Bottom water feed
You want to feed the water through the
bottom chamber, therefore, you need to pipe the water to the bottom of
the pond via a bulkhead fitting and PVC pipe.
Lay a piece of PVC the full length of the bottom, drill 1/4 inch holes every 8 inches and
cap the end of the pipe. This will help the water circulate through
the entire planting bed.
Planting
bed (optional*)
Lay a grate cut from bread crates or milk
crates or egg crate about 8" from the bottom. Put hardware cloth or
screening
on top of the chamber you've created. Fill with 1" to 2" sized river
rock, make sure you wash the rock first,-Do not use lava rock- a 3- 4" layer will
do- Plant with your favorite aquatics
and presto you have an easily maintained Bio Mass Filter. Naturally you
will need to make provisions for an outflow into your main pond, again
bulkhead fittings will do very nicely.
*
With Floating Plants no planting bed.
The planting bed
and it's maintenance can be eliminated if only floating plants such as Water Hyacinth,
Water Lettuce etc. are used. There is no free lunch however, floating plants
remove less nutrients, because the removal of the gravel bed encourages faster
water turnover and less sediment collection. Floating plants also require you to
keep them away from the outflow of the filter, as they will tend to collect and
plug the outflow, which may cause overflow and water leakage. We don't recommend
small plants i.e. Duckweed, Azzolla or it's many cousins since they will flow
through the filter into the main pond.
Overflow back to Pond
Two 2" Bulkhead fittings drilled as close to the top of the container as
possible and fitted with PVC outflow to the main pond will complete your Veggie
Filter.
A few words about
maintenance
Prune the roots of the plants every month
or so, or you will find the roots enveloping the gravel mass and eventually
tying all the gravel together in a bunch. Flush the bottom drain once a month to
rid it of sediment. |
