"Fine sand" called "Natural sand"
by the manufacturer Oldcastle industries.
50 lb bags.
Cover the pea gravel with 6 inches of this sand.
Also the graded sand used:
.15mm effective filtration size.
WARNING: Know exactly where the sand you use
comes from and what is in it before you ever drink
any water that has passed through it in your filter.
There are two standards used to approve materials
for use with potable water that suppliers/manufactures can
choose to use: (National Sanitation Foundation)NSF 061
(American Water Works Association) AWWA B100-01.
(recycled food grade plastic container 40 inches tall
22 inch diameter with large threaded lid):
91.44 cm (36 inches) of sand,
with 10.16 cm (4 inches) of water on top.
Diameter: 55.88 cm (22 inches)
Volume of sand:
224139.6 cubic centimeters (13678 cu in)
Volume of water on top:
24908 cubic centimeters (1520 cu in)
Volume of water held by sand:
112069.8 cubic centimeters (6839 cu. in.)
Total volume of water:
136962.5 cubic centimeters (8358 cu. in.)
Flow (as of April 9 2008):
with 4 inches (10.16cm) of water on top of the sand surface:
(32.44 liters) per hour
(8.57 gallons per hour or 1979.67 cu. in. per hour)
53.76 cubic centimeters per minute or .022 cm per minute
(.00864 inches per minute)
Flow (fiter had been frozen.
It was restarted as of Feb 8 2009):
with 7.9 inches (20cm) of water on top of the sand surface:
(72 liters) per hour
Flow (as of April 8 2009):
with 7.9 inches (20 cm) of water on top of the sand surface:
(42 liters) per hour
The filter is still in operation. As of March 1, 2010 the flow rate
is 24 litres per hour (6.3 gallons per hour). It has not been necessary
to clean the filter, although the flow rate has gone from about
40 litres per hour to 24 litres per hour.
PVC pipe used throughout the filter:
Schedule 20 pvc 1/2 inch unless otherwise noted;
no connections are glued.
A charcoal filter is used on the output
which uses 1 1/4 inch pvc schedule 20 pipe.
Leave one side unglued so the charcoal can be
changed. Use charcoal approved for potable water.
cubic inch = 16.387064 cubic centimeters
2.54 cm = 1 inch
1 US gallon = 3785.41178 cubic centimeters
1 US gallon = 3.78541178 liters
1 liter = 0.264172052 US gallons
(For the graded sand I would recommend using the same
size but use a sand that is designed specifically for
drinking water filters.)