Pond reference

Water Volume Measurements

1 US gallon = 0.833 Imperial Gallons = 3.79 litres
1,000 US gallons = 832.6 Imperial Gallons = 3,785.4 Litres

1 Imperial gallon = 1.2 US gallons = 4.55 litres

1 ton pond = 220 Imperial gallons = 264 US gallons = 1,000 litres
[Japanese Breeders to refer to their ponds volume in "tons" = 2200 lbs. of water]

Water Weight Measurement

1 US gallon = 8.35 lbs.
1 Cubic foot = 7.48 USG = 62.43 lbs.
[1 cubic foot is a "1 X 1 X 1" area]

1 Imperial gallon = 10 lbs.
1 Cubic Foot - 6.24 IMPG = 62.43 lbs.

To convert Imperial Gallons to US gallons, multiply X 0.83
To convert US gallons to Imperial gallons, multiply X 1.2

How to Determine the Volume of your Pond

This is key information to know as dosing of most medications relies on accurate measurements. Too much medication to result in fish deaths

Method #1 - calculate your cubic foot
This is not a very reliable method, especially when guessing dimensions. Even when measuring, most ponds are not square, so the margin for error can still be high. It is however, a starting point

Measure the ponds Length X Width X Depth in feet
This gives you the cubic feet of water
Multiply this by 7.48 to arrive at a US gallon measurement
ie. pond is 10 x 7 x 3 feet deep
10 X 7 X 3 = 210 cubic feet
7.48 gallons / cubic foot X 210 cubic feet = 1.570.8 US gallons
[all medications in North America that I know of are in US gallons]

Method #2 - Calculate by adding Salt
This method is very accurate and easy to but you do need a salt meter. We offer this service for free at our shop

1] Measure your current salinity in % [0.01% is typical tap water]
2] Add an accurately measured weight of salt [estimate at least 5 lbs. per 1000 gallons]
3] Measure salinity after salt has fully dissolved [minimum 4 hrs. but the next day is better]
4] Plug numbers in formula

[Salt added in lbs. X 12] DIVIDED BY [Salinity 2 - Salinity 1]
ie. salinity measured at 0.02% [S1]. 20 lbs. of salt added. After dissolving, salinity measured at 0.13% [S2]
[20 lbs X 12] = 240
[S2 0.13% - S1 0.02%] = 0.11
240 DIVIDED BY 0.11 = 2,182 US gallon pond

Standard and Metric Conversions
Volume Conversion
1 tablespoon = 14.8 milliliters [ml]
1 ounce = 28.3 grams
3 teaspoons is 1 tablespoon
1 tablespoon = 0.5 ounces
8 ounces = 1 cup
16 ounces = 1 pint
32 ounces = 2 pints = 1 quart
128 ounces = 4 quarts = 1 gallon
Metric Volume Conversion
5 ml = 1 Teaspoon
14.8 ml = 1 Tablespoon = 3 Teaspoons 118.4 ml = 1/2 cup = 8 tablespoons 236.8 ml = 1 cup

*Take the time to measure and note the volume of pond treatment bottle caps for easier dosing
Metric Reference
* 1 meter [M] is the datum for all Distance related metric conversion

1 inch = 2.54 centimetres
100 centimetres = 1 metre [M]
1 M = 39.37 inches
1 milli = 1/1,000 of 1 M
1 micro M = 1 um = 1/1,000,000 of 1 M

*Protozoa like costia are 10-20 um

pond plumbing flow rates and head losses

Pond Piping Flow Rates

A gravity fed water flow rate is a function of the diametre of the pipe and the distance below the water surface which creates the pressure

Every 27 inches below the water surface equates to 1 p.s.i. of pressure. This is good depth below pond level to run your pipe work [ie bottom drain feed] to ensure adequate flow rate into the filter

Gravity Fed System Set-up
If you undersize your plumbing and/or place your feed lines to close to the ponds surface, the flow to the filter will be poor and will not keep up your pumps flow output. The differential head loss will be too great

Pipe Diameter Area

Two 2 inch lines will feed less water than one 3 inch diametre line [with same layout]
2 inch line = radius squared x pie = 1x1 x 3.14 x 2 lines = 6.24 inches of area
1 x 3 inch line = 1.5 x 1.5 x 3.14 = 7.065 inches of area

Types of Head Losses

Static Head - The height the water is pump vertically from the pump out to the discharge point *this is the most important head loss to examine for most setups. Other head losses are converted to static head and this is the reference given on the pump box

Dynamic Head - Flow losses due to the water turning through elbows *minimize hard turns, flex hose is best

Friction Head - flow losses due to water resistance from both the diametre of the pipe and its sidewalls - the faster the water travels, the greater the friction head loss *match the pipe diametre with the pump

Pressure Head
- Pressure filters are notorious for creating a lot of back pressure. For example, a bead filter can cause 7 - 10 p.s.i. of pressure which will dramatically reduce flow rates

Differential Head - The water level in gravity fed filter chambers will be lower than the pond water level chambers. It requires some dropdown before a difference in level is created - this is what draws more water in. *ensure you use the proper diametre pipe down far enough below the surface so that the pump is not starved for water

Practical Example
Given a 1 foot wide waterfall, a range of 5 to 20 gpm [gallons per minute] would represent a decent flow to heavy flow. Lets say 10 gpm to make things simple and provide a solid flow rate of close the 1/2" thickness over a 1 foot wide waterfalls. 10 gpm = 600 gph [gallons per hour]. GPH is typical of pump box specs

Lets also assume the waterfalls is 3 feet high and you have a small pressure filter. These could combine to produce about 3 [static head] + 5 [pressure head] = 8 feet of head. You may have some turns [dynamic head], some friction head losses, so all toll lets say 10 feet of total head

Using the calculated requirement of 600 gph and the Total Dynamic Head of 10, were merely look at pump curve and figure out what would meet our criteria. Click the image left and you will discover that a model 3200 will deliver 650 gph at 10 feet of head - this is therefore the pump you need

Bulkhead Holesaw Sizes

1.5" Bulkhead needs a 2 1/2 inch Hole Saw
2" Bulkhead needs a 3 1/8th. inch Hole Saw
3" Bulkhead needs a 4 3/8th. inch Hole Saw
4" Bulkhead needs a 5.5 inch Hole Saw