MY RO/DI units lie horizontal to the RO unit. However, it appears to me
that the water channels along the top and don't actually pass through
the resin material.

I ordered some more resin to see if I could pack it in there better, but
are there any tricks of the trade. I'm tempted to just mount them
vertically with the water flowing up. I think it would work better.

Anyways, either my TDS is broken or I'm doing 0 ppm on the outflow.
Next time I shut it off I'll have to switch my output/input meters and
see if there is a difference.

--Kurt