Spectra
Pure
®
Inc.
480.894.5437 Call us toll-free 1.800.685.2783
215 South Industrial Drive, Suite 2A Tempe, Arizona 85281-2941
Spectra
Pure
®
Membrane Output
Calculation Example
What is the expected GPD from a 50 GPD MPRO-C System at 40 psi
pressure and 60°F water temperature?
PCF = 40 ÷ 60 = 0.666
TCF = 0.754 (from Table 1)
Expected GPD = 50 × 0.666 × 0.754 = 25.1 GPD ± 15%
Testing the Quality of the Membrane
The performance of a RO membrane is measured in terms of its
rejection characteristics.
Important:
Test the quality of the membrane once every 6 months.
Note: This procedure will require a Conductivity Meter (TS-C61).
Procedure:
Membrane Testing
1. Measure tap water conductivity.* (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 conductivity.* (Call it Y.)
5. Subtract RO water conductivity* from tap water
conductivity.* (X - Y)
6. Divide this quantity by tap water conductivity.* (X - Y) ÷ X
7. Rejection = [(X - Y) ÷ X ] ×100
* Conductivity in the above procedure could be replaced by
hardness, alkalinity, nitrate, phosphate, silica etc. (measured in
ppm or mg/l).
1. Tap water hardness = 150 ppm (X)
2. RO water hardness = 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 Hardness Rejection = 95.3 % Þ Membrane OK
Rejection of the RO Membrane
Calculation Example
12
Spectra
Pure
®
Inc.
Fax 480.894.6109 Fax us toll-free 1.877.527.7873
E-mail [email protected] Visit us on the web www.spectrapure.com
Spectra
Pure
®
Checking the
Concentrate to Purified Water Ratio
This procedure will be the most important factor in insuring that you
get the best possible results from your new system.
Failure to perform this procedure will void the pro-rated
Membrane Warranty.
In order to maximize the life of your
SpectraPure
®
RO Membrane,
you may need to adjust the ratio of the concentrate to purified
water. If not enough concentrate is allowed to flow past the
membrane during operation, the impurities can concentrate and
precipitate on the membrane surface, effectively clogging the
encapsulated RO Membrane. To keep this from happening, the
Concentrate to Purified Water Ratio should be checked and
adjusted at the highest temperature and pressure the system will be
operated at.
Procedure:
1. Open the cold water supply valve half-way and let the
system run for 1/2 hour.
2. Using two measuring cups, simultaneously place the
yellow concentrate tubing into one cup and the blue
purified water tubing into the other cup.
3. When the blue tubing cup has collected 2 oz. (or 100 ml.)
of water, simultaneously remove the tubing from both
measuring cups.
4. Note how many oz. (or ml.) of water the yellow tubing
cup has collected.
5. To calculate the Concentrate to Purified Water Ratio, divide
the number of oz. (or ml.) of concentrate by the number of
oz. (or ml.) of purified water.
Formula: Concentrate ÷ Purified = Concentrate to Purified Ratio
Examples: 8 oz (400 ml) ÷ 2 oz (100 ml) = 4:1 Ratio - Acceptable
10 oz (500 ml) ÷ 2 oz (100 ml) = 5:1 Ratio - Acceptable
6 oz (300 ml) ÷ 2 oz (100 ml) = 3:1 Ratio - Not Acceptable
If the ratio is less than 4:1 (as in the third example), the system
must
be adjusted by reducing the length of the flow restrictor capillary
tubing as described on the next page. After modifying the flow
restrictor, repeat the above test and recalculate the Concentrate
to Purified Water Ratio.
Operating Instructions
5