By: Eric Lim
a times, new koi hobbyists got caught with the love of nishikigoi. Not
knowing that koi do create lot of waste & need frequent
maintenance if the filter system is not done correctly, most proceed
to get a easily / cheaply done pond / filter & then proceed to buy
expensive koi – only to see one by one dying off.
most common problem is due to wrong design of the filter system
(especially the size of drain line), making cleaning of the first few
chambers tedious. So owner clean less often, causing water quality to
go bad, then koi getting sick – And after 2 yrs. of frustration -
Owner gave up!
The objective of
this article is to help new hobbyists to plan a good working filter
system and other useful tips, so as to make koi keeping an enjoyable
hobby and not be slave to the hobby.
By recommending a
near 13tons pond, this I felt is the minimum that one can go,
especially keeping out-door in our tropical weather. Remember that
water temperature can rise a lot in the hot afternoon sun. Also,
green algae will be a problem if the capacity of the filter is
insufficient. Actually for this problem, top shading is a must to
control algae growth. Most of our advance club members’ ponds have
top full shading. But remember to use strong wooden structure &
non-toxic paint or coating. `Chenghai’ wood is meant for out-door
use, can even be use submerge in the filter. All filter top covering
(to preserve biological bacteria growth) should also use this.
problem is – many ponds have objects/ pipes sticking out in the main
ponds, thereby causing injury to koi when it dash madly during
feeding, etc. Sometimes, the injury cannot heal over time and your
precious buy becomes a junk koi.
This capacity is
not meant to keep jumbo koi. Achieving 70cm growth is possible, with
low stock. But best to keep `bonsai’ koi for high stocking. Still,
knowing new hobbyists, they tend to over-crowd. Hence the filter
system is 40% of the total capacity. Or 60% of the main pond.
The key things to
No objects sticking out in the
main pond to prevent injury.
Top shading is required if
exposed to long hours of sunlight. Will reduce much algae growth.
Depth of pond – not less
than 5 feet. Best if at 6 feet & more. In the afternoon,
surface will heat-up and koi will swim down to stay cool.
Cleaning of CH1 is daily or minimum, 2 days once. Pending the amount
of dust, CH2 & 3 may also be as regular. If not – clean weekly.
Be discipline & keep good water by regular cleaning. The koi will
stay healthy & take care of itself.
Size of drainage (here its 4ins.) – larger means drain faster, you
clean happier & more regularly. Don’t let the contractor
out-talk you into a smaller size, to save budget. Think long terms. At
least 3” minimum.
Biological bacteria do not establish after 3 feet depth. So no point
having a deep filter. Shallow depth makes it easier to view
Electrical Points – best to install different circuit breakers for
both water pumps as most cheap mechanical-seal pump only has a life
span of 2 to 3 yrs. If one trip causing all power supply to stop and
no one is at home for long hours – expensive mistake. If you only
have one water pump & one air pump – also use two CB points. Koi
will not die as far as there is air circulation in the main pond. Air
pump does not trip. UV unit needs electricity too.
Pump turnover rate – the total capacity should not be less than once
/ hour. Present design using two OMU-2 pumps (total capacity =
26,400 liters /hr.) is 2 times / hour.
Back flushing from
P2 – use this for back cleaning of bio. chambers. Do not use tap
water to back wash.
If pH is low (6.5 or
<), convert CH 6 to hold coral chips in holding bags for easier
cleaning. Dirty chips not wash can caused `Hikkui’ disease.
To clean CH1, pull out PP No.1 (pull pipe), plug into 4” inlet (to
stop flow) & pull out BP1 (by-pass) to continue the filter flow.
Pull out PPA to drain to dry sump. Pull out PPF to drain to sewer.
To clean CH2 & 3, pull out PP No.2 & 3. Pull out BP1 (by-pass)
to continue flow. Pull out PPB to drain to dry sump & PPF to
To clean CH4, 5 & 6. Pull out BP3 (by-pass) to continue pumps
outlet. Pull out PP4 & PPA for CH4 and PP5, 6 & PPE & D
for CH5 & 6 to drain to dry sump. PPF - to sewer.
To drain pond bottom, pull out PPC & PPF to drain to sewer.
Overflow points –
As no pipes are to protrude out, all up-turn inlet elbows are recess
into the filter chambers.
OF No.1 (over-flow)
– is set at just below the usual water level. This is a continuous
flow, to skim & maintain the water surface sparking clean. OF 2 is
lower by 3in than OF 1, for by-pass use.
OF 3 – is set
higher by 2 inches from OF 1. In the event oily or dusty surface was
encountered, top-in tap water to increase the height & continue a
flow to skim out the scum. OF 1 is shut-off.
Converting CH No.1
chamber into a hospital/ quarantine tank – Pull out BP 2 (by-pass).
OF 2 short pipe swap over to cover OF 1. Insert a 4” pull pipe to
close up the inlet. See Note 1 & 2 = the heights are different. By
dropping usual water level, CH 1 is isolated by itself. Inlet now
starts at BP 2 (CH 2).
isolating the main pond and convert filter system to self-circulation
– Pull out BP 3 & plug up CH 1 inlet. Drop usual water level
till below CH 6 outlet level. Disconnect water pump P 2 and put into
CH 6. Run a hose to CH 2 and start P 2 circulation.
This is meant to be
a last resort in situation where all koi are infected. Always practice
the habit of quarantine all newly purchases and to catch & treat
any sick/ injured koi ASAP, outside.
Note: If Dry Sump
is lower than outside sewer, a powerful water pump with Auto-Low Level
cutout must be used to push out the drained water fast.
Filter Pump use
Model : OMU-2 (cost
Max cap. 220
liters/min (13,200 l /hr)
Head/Max : 5.2m
Wattage : 150W