R/O-DI water and brass valve

[gregt]

Great job with the forum, I've learned alot already!

Will a brass valve such as I'm using on my R/O-DI be a problem? The question recurringly comes up that corrosion could be an issue.

<CENTER><TABLE><TR><TD COLSPAN = 3><CENTER><IMG SRC=http://saltyzoo.com/180/equipment/011124/gt011124_0927_60-cp-640.jpg></CENTER></TD></TR><TR><TD COLSPAN = 3><B>GT011124_0927_60-cp</B> - From the DI filter the line goes to a trash can. The brass valve is to turn the system off when not in use. The float valve is to shut off flow when the trash can is full.</TD></TR></TABLE><TABLE CELLSPACING=20><TR><TD><A HREF=http://saltyzoo.com/Photo.jsp?urlStr=/180/equipment/011124&name=gt011124_0927_60-cp-640>640x480 (26.0K)</A></TD><TD><A HREF=http://saltyzoo.com/Photo.jsp?urlStr=/180/equipment/011124&name=gt011124_0927_60-cp-800>800x600 (59.0K)</A></TD><TD><A HREF=http://saltyzoo.com/Photo.jsp?urlStr=/180/equipment/011124&name=gt011124_0927_60-cp>Hi-Res (62.0K)</A></TD></TR></TABLE><TABLE><TR><td align=center><a href=http://saltyzoo.com/Photo.jsp?urlStr=/180/equipment/011124&name=GT011124_0927_58-cp-640><img src=http://saltyzoo.com/buttons/left.gif border=0></a></td><td align=center><a href=http://saltyzoo.com/PhotoAlbum.jsp?urlStr=/180/equipment/011124><img src=http://saltyzoo.com/buttons/home.gif border=0></a></td><td align=center><a href=http://saltyzoo.com/Photo.jsp?urlStr=/180/equipment/011124&name=GT011124_0927_61-640><img src=http://saltyzoo.com/buttons/right.gif border=0></a></td></tr></TABLE></CENTER>

TIA,

[Randy Holmes-Farley]

A brass valve will POTENTIALLY release copper to the water, and presumably that's bad due to copper toxicity to many inverts. Ron would tell you to avoid any unnecessary copper. Personally, I'd wouldn't use it.

Greg Hiller once measured the copper that came from his pipes and it was substantial (i.e., too much). Would this valve release too much? I don't know, but I would try to design a system without it.

[gregt]

Thanks, I was always under the impression that RO/DI water would not corrode brass appreciably.

I'll find another solution.

[Randy Holmes-Farley]

I'm sure it won't from the standpoint of appearance of the valve or it's operation. The problem comes about because copper is toxic at such low levels that some of the copper coming off of the valve may be harmful, even if the valve looks perfectly OK.

For comparison, 1 cubic millimeter of copper metal (9 mg of copper) is enough to raise 35,000 liters of RO/DI water to NSW concentrations (0.00025 ppm). I don't know the amount required for toxicity, but Ron has said that it isn't all that far above the natural levels.

[Snailman]

You can find plastic ball valves the will fit right on your 1/4" plastic line at www.usplastic.com part #58309 $4.85 each.