SpectraPure The Eliminator Operator's Manual page 20

SpectraPure
Membrane Output Calculation Example
What is the expected GPD from a 75 GPD System at 40 psi pressure and 60°F
water temperature?
PCF = 40 ÷ 60 = 0.666
TCF = 0.754 (from Table 1)
Expected GPD = 75 × 0.666 × 0.754 = 37.7 GPD ± 15%
37.7 GPD would be the Actual Production Rate
TESTING THE QUALITY OF THE MEMBRANE
The performance of a RO membrane is measured by its ability to reject salts
Important: Test the quality of the membrane once every 6 months.
Note: This procedure will require a TDS Meter. SpectraPure offers several models.
Procedure:
1. Measure tap water TDS. (Call it X)
2. Run the system for 15-20 minutes.
3. Rinse test instrument cell 2-3 times with RO water.
4. Measure RO water TDS directly from the blue product
water line. (Call it Y).
5. Subtract RO water TDS from tap water TDS. (X - Y)
6. Divide this quantity by tap water TDS. (X - Y) ÷ X
7. Rejection = [(X - Y) ÷ X ] ×100
* TDS in the above procedure is measured in ppm or mg/l.
Rejection of the RO Membrane Calculation Example
1. Tap water TDS = 150 ppm (X)
2. RO water TDS = 7 ppm (Y)
3. X - Y = 143 ppm
4. (X - Y) ÷ X = 143 ÷ 150 = 0.953
5. Rejection = [ ( X - Y) ÷ X ] ×100 = 0.953 ×100 = 95.3
Membrane TDS Rejection = 95.3 % : Rejection rates less than 95% may
indicate that the membrane should be replaced.
SpectraPure®Inc.
2167 East Fifth St, Tempe, Arizona 85281
20
®
(or TDS (Total Dissolved Solids)).
480.894.5437 Call us toll-free 1.800.685.2783