Copper with 0 TDS

[maxwell50]

Hello

I have 4 stage BRD Rodi unit with water saver . My membrane is rated for 100gpd x2.Recently I tested water with Hanna copper check and got a reading of .21ppm and I made new batch of water and got .33pm. I tested my rodi water and got .26ppm. I also had some older rodi water which tested .01ppm. My output TDS is 0 am confusing how is this possible. What can I do to solve this problem I replaced one membrane and looking to replace the other one soon. All other filter maybe 6-8 months old I think

 

[EmdeReef]

Between the RO Membrane and the DI, copper should be removed. I would replace the membrane and DI resin. Your carbon blocks may be too old as well.
is the water running through any metal pipes or getting in contact with metal?

At 0 tds there should not be too much copper, assuming your tds meter is accurate.

 

[maxwell50]

Between the RO Membrane and the DI, copper should be removed. I would replace the membrane and DI resin. Your carbon blocks may be too old as well.
is the water running through any metal pipes or getting in contact with metal?

At 0 tds there should not be too much copper, assuming your tds meter is accurate.

I test water straight from rodi tube. I didn’t see any metals I did start using new plastic container

 

[maxwell50]

Changed micron and carbon copper went dow