TDS Troubles

[rhumphry]

Help!!
I have a 5 stage 200 GPD RO/DI System from Bulk Reef Supply. I just changed the membranes, carbon, resin and sediment filters and could not get a better reading than 10ppm. Coming from the well, I get 58 ppm. I even purchased a new TDS meter and it is consistent with the 10 ppm. Any advise to get me to 0 ppm would be greatly appreciated.

 

[ptrahan]

Try measuring tds after RO. Compare to post DI. TDS after RO should be no greater than 3-5. After DI should be zero. Also try flushing each stage for a few minutes, starting at the sediment filter and working your way to the DI. Make sure bypass is closed afterwards.

 

[Bulk Reef Supply]

New membranes require a hydration time to bleed off any preservatives on them that keep them from drying out before use. For this, we recommend running the RO unit in production mode without DI resin until you make 5-8 gallons of RO water. Then install the DI resin back and you should be set.

Also, ensure the last stage of your resin is mixed bed resin, not just Anion or Cation resin as a mixed bed will ensure that the water isn't loaded with excess hydroxide or hydrogen ions from a single bed resin.