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Revision date: 03.21.18
115295
Adjust Flow Rates
Congratulations! Your aquaponic system is now constructed and tanks and
raft bed are filled with water. Now it is time to dial in your system to make
sure it functions properly. To do this, adjust water flow to each fish-holding
tank using ball valve on each inlet.
The chart (upper-right) shows the flow for fish tank(s) and total flow for the
system. Use this information to measure and set the correct flow.
System
Number of
Fish-Holding Tanks
Tank Flow
(gallons per minute – gpm) Total Flow
I
1
4
4
To measure the flow of water into one (1) fish tank, you need to time how long it takes to fill a known volume with water. An easy way to do this is mark the
exact five (5) gallon level on a typical 5-gallon bucket. This is done by pouring a known volume of water into the bucket and marking the level on the bucket.
Water can also be weighed. Five (5) gallons of water weighs 41.7 pounds at room temperature.
Once you know the exact level of five (5) gallons in the bucket, take a stopwatch and time how long it takes the tank inlet pipe to fill the bucket up to that level.
Use the formula below to determine how long it should take to fill a “known volume” of water.
If the desired flow into a tank is 20 gallons per minute, it will take exactly 15 seconds to fill your
bucket to the line.
Known Volume (gallons)
Desired Flow Rate (gpm)
x 60
= 15 seconds
5 gallons
20 gpm
x 60
If bucket fills faster, restrict flow to tank by slightly closing inlet ball valve. If it takes longer than 15
seconds, slightly open valve to increase flow. After you have dialed this in for the first fish tank,
move to the next tank (if present) and repeat the process. After setting flow rate for all fish tanks,
recheck each tank to ensure rate remains at 20 gallons per minute. Adjust flow as needed. Repeat
as needed to confirm all tanks flow evenly.
NOTE:
Recheck flow rates after pump runs for at least 15 minutes to ensure all air is out of the
lines and pump is at a steady-state flow. If fish tank is filled, simply place bucket under inlet fitting.
As bucket fills with water, it will begin to sink in the tank. Do not let tank water flow into your bucket
as it will skew results.
After setting flow rates for fish tank(s), monitor water level in raft bed. Flow
from
clarifier tank
into raft bed should match flow into fish tank(s). Check flow rates an hour or two later. When set
correctly, raft bed should not overflow.
= Time (seconds)
Fish Tank
Adjust valve to
control flow.