4.3 Aquaponic Growing System
4.3.1 Plant and Fish Ratio
The recycling mechanism of nutrients in the aquaponic system requires careful planning on how much
fish, water and growing space is needed to achieve optimum growth. Initially our calculations showed
(see Appendix) that one fish required 3.5 gallons of water. The waste material from this one fish could
support one square foot of growing bed. However research conducted by Aquaponic Specialist Sylvia
Bernstein had different ratios and these differences are shown in table () below. (Bernstein, 2013)
Criteria For Greenhouse IQP Findings Sylvia Bernstein Findings
Assumed Weight of 1 Fish 1 Pound 1 Pound
Gallons of Water required per
Fish3.5 Liters 5 - 10 LitersGrowing Bed Area Supported
by 1 Fish1 Square foot 1 Square footTable 17 : Comparison Of IQP and Bersntein Ratio Findings
The table shows that similar ratios and assumptions were made. The only Criteria that was vastly
different was the amount of water needed to support one fish. The Calculations of the IQP group
seemed to underestimate how much water was needed by each fish. Therefore an average value of the
Sylvia Bernstein findings (7.5 Gallons of water per fish) was used as a bench mark for the design of how
much water, tanks and how much growing beds could be supported by the system.
4.3.2 Growing Bed: Wooden Bed vs 55-Gallon Drum.................................................................
Beddings are a very important part of a greenhouse setup. Growing beds are where the plants get their
nutrients and grow. There are several types of growing beds that are used in an aquaponics setting.
Some are available commercially and others can be easily made with materials that are readily
inexpensive and easy to acquire. We considered two types of beddings; a custom made wooden bedding
box, and 55-gallon plastic drum cut vertically in half.
4.3.2.1 Wooden Box Growing Bed
This option was to construct a custom wooden box using readily available materials, and then using a
pond liner (found at any home improvement store) to line the bed. Table 18 shows the cost breakdown
of the growing bed. We designed the bed to maximize the use from standard sizes of plywood.
Item Cost Quantity
¾” x 4’ x 8’ Plywood $34.98 x2
2” x 4” x 8’ Wooden
Reinforcement
$2.76 x5
Pond Liner 10’ x 13’ $59.97 x1
Total Cost For One Bed $132.69
Table 18. Bed Cost Breakdown for One BedThe bed is made from plywood and has 2x4 boards wrapped around the entire outside of the bed for
added support. Water is quite heavy and this places stress on the components. The pond liner contains
the water as water may seep into wood and leak, as well as causing the wood to rot. A pond liner is an