Spectra Watermakers CATALINA 300 MPC-5000, Installation & Owner'S Manual

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Operation and Repair Bulletins
The following documents are sections of our complete service bulletin set.
These are available on our website at www.spectratermakers.com
MB-2 MEMBRANE CARE
Membrane life is affected by a large number of factors and is somewhat unpredictable. A big
commercial plant running 24/7 will get 10 to 12 years out of a set of membranes. But they do
all kinds of fancy chemical injections and never shut the thing off. Most cruisers are lucky to
get five or six years out of one. You hear of the eight or ten year old membrane now and then.
The biggest killers of membranes are lack of use, chlorine damage, and improper storage.
Don’t let membranes sit around with sea water or stale fresh water in them. Biological growth
will occur in the membrane. Here at the factory we frequently get back membranes for inspec-
tion that reek of hydrogen sulfide (rotten eggs). This odor is produce by anaerobic bacteria that
live in an unused membrane, feeding on whatever animal or vegetable matter is trapped in it
from the plankton that gets through the system. Membranes badly fouled in this way can sel-
dom be saved. These bacteria are always present but are inhibited by the oxygen in sea water
while the unit is in frequent use, by scheduled fresh water flushes, or by pickling. Keeping the
prefilters clean is also important in preventing bio-fouling. If your prefilters are allowed to be-
come a breeding ground for bacteria (get smelly), the contamination will spread throughout the
system. When we cut open a failed membrane we also find mildew, another form of bio foul-
ing, probably due to long term storage with no biocide or stale biocide.
After many hours of water making mineral deposits will form and must be dissolved away with
an acid cleaner. Alkaline cleaners are used for bio-fouling. Cleaning chemicals, especially the
alkaline, are not good for the membrane. Every time you clean the membrane it shortens its
life. Clean only when necessary, and avoid cleaning as a “diagnostic tool”.
Chlorine will destroy a membrane in minutes. It attacks the material that the membrane is made
from. Always use product water or water filtered slowly through a charcoal filter for flushing
and chemical treatments.
Oil simply plugs up the matrix of the membrane and clogs it up. We have brought back oil
fouled membranes with Joy soap (See MB-5 Cleaning with Detergent.)
For storage we recommend using propylene glycol potable water system antifreeze if available.
It can safely be left in the system for one year and will keep things from freezing in cold condi-
tions. It is hard to find in warm climates, and takes up a lot of room on a small boat, so our SC-
1 is best for tropical cruising.
Given good care a membrane will eventually just start to slowly fade away. The feed pressure
may rise and/or the ppm go up. Hardly ever will they just fail overnight.
8/13/04