IV. Testing Filters
Reverse Osmosis membranes have a variance in their filter life and this is affected by several things
including water quality, usage, temperature and filter maintenance. As they are the workhorse of the
system, they are the most important filters to monitor and keep maintained.
To measure the effectiveness of the RO membrane you will need a TDS/EC test meter. Draw a sample of
tap water (to get your base reading), then collect a sample of water directly off the membrane outlet (before
it goes through any other filters). This is your ‘pure’ water. To calculate the membrane effectiveness, you
will need to subtract the percentage of contaminant reduction from the feed water. E.g. Feed Water
200mg/L TDS – RO Membrane removes 97% (+/-) Therefore, 200 – 97% = 6mg/L. Factors can influence
the final TDS of the water and it will depend upon what is in the feed water to begin with. A membrane is
deemed to be ‘expired’ if the overall reduction rate is <90% (as a general rule). To apply this to the above
example, 200 – 90% = 20mg/L. So, if your test reading was approaching 20mg/L or higher, it would be time
to change the membrane.
Troubleshooting
Problem
Possible Cause
Solution
Water Leaking Between fitting
and tubing.
Unseated Tube
Check all tubing connections by
firmly pushing them into the fitting.
Check that there are no kinks or
any obvious issues. If the problem
persists, remove the tubing and
check for a clean cut with no burs.
Push the tubing back in and try
again. If this does not work please
contact customer support.
Water Leaking Between Fitting &
Filter
Fitting not tight enough /
Insufficient Thread Tape /
Damaged Fitting or Filter
If the fitting appears to be not fully
tightened, gradually tighten the
fitting to see If this fixes the leak. If
this does not work, remove the
fitting and check for any signs of
damage either on the fitting or the
female port of the housing. If there
are no obvious signs of damage,
apply white plumbers’ tape. Use 6
rounds for 1/8” fittings (membrane
housing fittings) and 8 rounds for
all other ¼” fittings.
Water Is Leaking from My
Diverter Valve
1. Damaged/Missing Washer
2. Not Tight Enough
3. Thread is too Short
1. Check the diverter valve to see if
the washer is inside, if it is
damaged it may need replacing –
this is a common size washer and
can be purchased from most
hardware/plumbing stores.
2. If the diverter valve is loose (or
you can easily swivel the fitting
without resistance, the fitting is not
tightened enough. It may feel like
you can’t tighten it anymore and it
just keeps spinning but if you use a
gripping tool (multi grips) to grab
the collar of the fitting and use your
hand to hold the valve itself steady,
you will be able to further tighten
the valve. The valve is tight
enough when you feel light to
moderate resistance when trying to
swivel the valve.
