I meant DW not DS below.

________________________________

 
 Is there any chance you have contaminated DS? This could explain the
low level of CS if it is contaniminated but not bad enough to trip the
water quality monitor in your generator. It could also be that the unit
isn't operating correctly. I think your observations of a faint beam
with the laser pointer indicates low ppm CS. Is there anything you are
doing during the process, such as cleaning the electrodes that could
cause contanimation? You could also try running the same batch twice if
the generator will let you.  With a digital multimeter you could check
your setup for voltage and current:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92020
<http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92020>


Or get a TDS meter: 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170250480664&ssPageNa
me=MERC_VIC_RSCC_Pr12_PcY_BIN_Stores_IT&refitem=170239081511&itemcount=1
2&refwidgetloc=closed_view_item&usedrule1=StoreCatToStoreCat&refwidgetty
pe=cross_promot_widget&_trksid=p284.m183&_trkparms=algo%3DDR%26its%3DS%2
52BI%252BSS%26itu%3DISS%252BUCI%252BSI%26otn%3D12
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170250480664&ssPageN
ame=MERC_VIC_RSCC_Pr12_PcY_BIN_Stores_IT&refitem=170239081511&itemcount=
12&refwidgetloc=closed_view_item&usedrule1=StoreCatToStoreCat&refwidgett
ype=cross_promot_widget&_trksid=p284.m183&_trkparms=algo%3DDR%26its%3DS%
252BI%252BSS%26itu%3DISS%252BUCI%252BSI%26otn%3D12> 

It might be worth the expense. 
 - Steve