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Discussion Starter · #1 ·
I recently installed a dual input TDS meter on my filter unit. The output of the DI filter is tubed to a float operated solenoid valve then to a 25 gallon reservoir. What I'm seeing is that when I remove water from the reservoir and water begins to flow through the filter the TDS after the RO membrane is high, anywhere from 70 to 180. The TDS gradually comes down to around 12-15 after 2 or 3 minutes and stays there until the next time I use water. The output of the DI stays at 0-1 ppm. Seems like the "spike" up to 1 corresponds with the high input TDS.

What does this mean? Time to replace the membrane? Or maybe the block that has 2 lines going to the RO, one to the drain and one to the DI? I see that part and the drain check valve are part of the filter's maintenance kit.
 

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its normal. its called tds creep. when u dont use the machine for a few days the tds will rise from the ro side then after a few minutes it will go back down.hth
 

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All RODI systems should have a flush valve on them or if not get one.

These flush valves are cheap to purchase and easy put on the RODI system.

Before making RODI water flush the system for 1 minute.

This eliminates the dirty water sitting stagnant in the membrane and filters.

This will lower your initial TDS levels prior to making your RODI water.

Have a great day.
 

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Discussion Starter · #5 ·
dentdominator said:
All RODI systems should have a flush valve on them or if not get one.

These flush valves are cheap to purchase and easy put on the RODI system.

Before making RODI water flush the system for 1 minute.

This eliminates the dirty water sitting stagnant in the membrane and filters.

This will lower your initial TDS levels prior to making your RODI water.

Have a great day.
Where in the system does the flush valve go?
 

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You want your flush valve to mount in your concentrate line that exits the membrane but before your restrictor so that you can bypass your restrictor and get full water pressure to rinse off your membrane and flush the housing.


I just made mine out of a couple t-fittings, some extra tubing I had and a shut off valve.
 

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Discussion Starter · #8 ·
TM01 said:
You want your flush valve to mount in your concentrate line that exits the membrane but before your restrictor so that you can bypass your restrictor and get full water pressure to rinse off your membrane and flush the housing.

I just made mine out of a couple t-fittings, some extra tubing I had and a shut off valve.
There are three lines on the RO. The feed is obvious but which of the other two is the concentrate line? Both of the other two go to this block which I'm assuming is the restrictor.
 
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