Koi Rescue
Phoenix Arizona



Rules Of Thumb, Weights, Densities and other Data



-- CALCULATE SIZE OF POND ---
62 lbs of water per cubic foot
8.2 lbs per gallon of water
7.56 gallons per cubic feet
228 cubic inches per gallon

-- MATERIALS ---
80 lb bag of pre-mix concrete cost $2.86 ea
4x8x16 cinder block = 24 lbs, cost $0.72 ea
8x8x16 cinder block = 39 lbs, cost $1.09 ea
3/8" x 10' rebar is $2.58
1/2" black poly pipe, 500' roll is $29
1-1/2" pvc pipe is $4.50 per 10' stick

-- CONCRETE TIPS ---
80 lb bag of pre-mixed concrete is 2/3 cuft (or rather 1157 cuin)
40 bags per cu yard
water per bag -- I fill 8" worth of water in a 5 gallon bucket, and use for 2 bags
5:1 ratio of concrete mix (5 of sand and rocks, 1 of portland cement)
Lime is only added to retain water and extend working time.
Stucco is 5 parts of #30 sand, 2 parts of lime, 1 of portland cement
Stucco is best smoothed 30 minutes after slapped on.
On the show "Dirty Jobs", they used 1 part portland, 2 parts sand to repair brick sewer canals
Better stucco -- packmix type S high strength mortar / stucco
sugar is good retarder - used for exposed aggregate finish

-- Main Circulation Pump ---
many websites say change all water in 2 hours -- so 1500 gal pond needs 750 gph pump

-- Calculate Electric Use ---
Watts = Volts * Amps.
My 600 gph pump is a 35 watt, which runs on 110 volts.
35 watt pump x 24 (hrs in a day) x 31 days = 26040 watt hours per month
= 26.040 kwh per month
* 0.0701 dollars per kwh (cost of electricity)
= $1.8 per month
It is a cheapo $35 submersible from Harbor Freight, that is a pretty low operating cost and if it goes bad, I can just get another one later.

-- Biofilter Media --
Kaldnes K1 media has 259 sqft of area per cubic foot of media, and has supposedly been proven in aquaculture applications to be able to process 2 ounces of 40% protein food, per day, per 1 gallon of K1 media in a moving bed filter. Most koi filter manufacturers rate it at a lower effeciency, they rate it at 0.61 ounces of food, per day, per gallon of K1 media. Although I saw one that rated it at 0.83 oz per gallon.
Other K1 info -- have heard can only fill a container 40% of the way full with the media, and still get it to boil. Also the media has to have algae and other growth on it before it will boil. Otherwise it floats right out of the box and won't boil.
Bilballs (biopin) are around 160 sqft per cubic foot of media, so only have 61% of the square area per cubic foot of K1. So assuming you can use the same rating, they would handle 0.37 ounces of 40% protein food per gallon of bioball media.
Example filter with bioballs:
So a 55 gallon drum, filled up with 25 gallons of bioballs should handle 9.25 ounces of food per day.
If feeding 1% of the weight of the fish per day, that is 925 ounces of fish.
A 26" koi weighs about 160 ounces, so that filter will handle 5.7 of those size koi


-- Pipe Size for low pressure & gravity return --
1/2" = 300 gph
3/4" = 600 gph
1" = 780 gph
1-1/4" = 1380 gph
1-1/2" = 2100 gph
2" = 3300 gph
2-1/2" = 4500 gph
3" = 7500 gph
4" = 12000 gph