(This is a thread copied from the OCC Members Facebook Group)

After recommissioning your water maker, how long do you run it, discarding all product water overboard, until you’re happy to put it in the tank?

REPLIES
•    30 minutes of flushing for a Spectra 300.
•    Until the TDS is below 200 and it tastes good. Taste is the real key. Whenever we first started using a watermaker we forget to drain the seastrainer and it would get hydrogen sulphide smelling- even thoughTDS was low it still smelled awful. Now taste and smell are our guides. Plus we drain the seastrainer after every use. But to answer your question our Cruise RO takes about 3 minutes to start making good water.
             o    i was more concerned with how long it takes to flush out the pickling chemicals after layup.
             o    Sodium metabisulfite? Easy to rinse, they use it in bars to sanitize glasses. Again, taste and smell are key.
             o    ok great perhaps I don’t need to worry too much.
•    We go by taste. Usually a few minutes. In practise it happens quickly due to the flow rate of seawater going through the membrane. Our manual advise running the machine for 5 minutes before switching over to tank.
•    I run LP pump for 5 mins, LP and HP pump (but no needle valve pressure..flush mode) 15-25 mins then dial up pressure and discard next 5 mins product water. I also dial up pressure very slowly..kept membranes going almost 10 years!
•    Twice as long as you feel is enough. We were very careful only to put best quality water into the tanks. We would also double filter any marina water going in. Also we would make sure we never flushed the water maker with chlorinated marina water. Water makers are very precious so we always be extremely cautious.
•    Lol....guess I’m more conservative than I thought! 10 min on hp directing product overboard after pickeling...then double checking TDS, taste & smell.
•    Get a water tester, they are cheap and easily available, even on Amazon. Game changer. Your sense of taste is just not good enough to sense the right low PPM reading. ~$20 for health and peace of mind. We worked on taste for years and were well off the mark until advised to get a tester by a fellow cruiser. It's also really useful to quickly spot if your membranes are staring to deteriorate.
                       o    The testers are like a fat flat pencil with a small LCD screen to show the results. Draw a glass of the water to be tested and place the tester in it; you get an instant readout of PPM so can tell straight away if it is safe to drink.
•    I don't like the taste until it has run for at least 30 minutes.
•    I suppose the volume of flow has something to do with the time needed to properly flush. A 40gpm AC pump probably more quickly flushes the membranes, even though they have a larger area, than does a 7gph DC pump.
•    The Owners Manual for our Cruise RO SM40 states " After the system is stable at 800psig, wait one minute and then collect a sample of the product drinking water and check the TDS....once acceptable (below 500ppm) the water is ready to be sent to the ships tank." YMMV!