The authoritative public forum
  for Metal Finishing 1989-2025
  

  -----

Can plating shop store batches of DI water

In our plating department we periodically require more DI water than our unit will produce. What do I need to watch for in storing approximately 200 gallons to top up supply when required. i.e. -keeping storage tank closed -is it possible to use uv sterilization and circulation of stored water.

Thanks,

Kent Lipskie
plating operation - Walkerton, Ontario, Canada
2004

---

What we do in our shop is to have a 500 gal closed top poly tank where our RO water is stored, and then continously pumped and regenerated through a DI unibed. We then pump water to our line as needed from that tank. We maintain about 10 meg water quality, which is plenty adequate for our application.

Marc Green
anodizer - Boise, Idaho
2004

---

Kent,

You might want to watch out for a pH reduction in the stored water. Atmospheric carbon dioxide will dissolve and lower you DI pH a bit. Might not matter in your application. I found that a recirculation pump helps control microbial growth.

Trent Kaufman
electroplater - Galva, Illinois
2004

---

Most larger systems include a DI water storage tank. In an atmospheric tank there will be some loss in the resistivity due to Carbon Dioxide dissolving in the water, and a slight drop in pH. Neither of these is important in most metal finishing operations. A UV light will retard biological growth, but not completely eliminate it. We recommend recirculating the stored water through a UV light at a rate that will turn over the tank every 2-3 hours.

Lyle Kirman
consultant - Cleveland Heights, Ohio
2004