RO/DI unit tds

etpelle72

New Member
I finally broke down and brought an ro/di unit and have been using it for about three months now. I have noticed that the tds on my product water has started going up when i first start the unit the product tds goes from 0 to 24ppm quickly and then in about a minute or two drops back to 0ppm. Should i just go ahead and replace the di now or wait until the tds stays above 0ppm? Oh and the unit does do an automatic back flush for 15seconds.
 

DaveK

Well-Known Member
My thinking, which may be wrong here, is that this is more dure to your TDS meter, rather than the water itself. Usually if the DI resin is used up the putput water will show a TDS reading no matter what.

If you want to check it out further, you could change your DI filter and see what happens. Keep the old one since it still might be good. If you still see the same thing occurring, then your likely ok, and can go back to using the original DI filter. Don't worry about the new one since you'll use that in time anyway.

One last thought. Make sure your mechanical filter and carbon filter on the unit are good. They should be, but sometimes in water with a lot of sediment they can part;y clog quickly.
 

Nobbygas

Well-Known Member
I use a DI Resin filter where the resin changes colour as it is being used up. Off the top of my head I can't remember the manufacturer. The DI unit itself is plastic, so you can see the resin change colour, and even before I measure with a TDS meter I can quite clearly see if the resin needs replacing.
 
Top