Specifications

Checking Quantity Produced
Measure and record both the flow rate and temperature of the product water. Record the temperature correction factor from Table
3 which corresponds to the measured flow rate to the 77°F (25°C) standard as follows:
Adjusted Measured Temperature
Flow = Flow ÷ Correction
Rate Rate Factor
As an example, if the above system is producing 24.15 gpd at 60°F, the Temperature Correction Factor from Table 3 is 0.69.
24.15 gpd ÷ 0.69 = 35 gpd @ 77°F
The TDS levels of the product and feed water were measured in the previous section. To accurately predict the performance of the
RO module, the feed water pressure must be adjusted to account for osmotic pressure. Calculate osmotic pressure as follows:
Osmotic Pressure = 1 psi for every 100 mg/L TDS
From the previous example system:1000 ÷ 100 = 10 psi Osmotic Pressure
Since osmotic pressure acts as back pressure against the RO process, it is subtracted from the measured feed water pressure to
determine the effective module pressure. Measure the feed water pressure and calculate the effective module pressure as follows:
Effective Module = Measured - Osmotic
Pressure Pressure Pressure
If the pressure measured from our example system is 60 psi: 60 - 10 = 50 psi Effective Module Pressure
Using the effective module pressure, read the standard product flow rate from flow graphs 2, 3 and 4. For our example system, we
find the standard product flow is 35 gpd at 50 psi. Comparing this to the adjusted flow rate, we find the example system operating
within the limits of the published standard.
Checking Quantity Stored
Following the guidelines below will allow you to predict the volume of water which will be stored by the tank as well as reduce the
risk of damage to the storage tank.
The storage tank uses a rubber bladder attached to the tank wall with air pressure on one side to push product water out of the
tank. This bladder is stretched when the tank is filled with water. Too much stretching can damage the bladder or pull it away from
the tank’s wall causing failure. We’ve prepared a easy method to determine the proper air pressure based on the application’s
requirements.
The 70% rule
We recommend that the tank never hold more than 70% of its internal volume as water. Table 2 lists the water volumes versus
tank size based on air pressure and product pressure. Values are listed for 5, 10 & 15 psi air pressure settings. Note: Before
using the table adjust the influent water pressure to product pressure.
Influent Water Pressure x 0.67 = Product Pressure
22 Aqua-Cleer
®
/ Good Water Machine
®