Inline TDS reading weird

[chudly]

I have one of your units with a double DI chamber at the end. The double DI chamber was an add on. My inline reading coming IN is (o) and my reading going out is FOUR. I just changed my first and second stage filters last month. Could it be that my probes are mixed up? I bought this unit used so i really don't know much about it. Where would the water pic up TDS after the membrane. I also checked my water with a hand held unit and it reads zero.
That's an old pic by the way. The membrane is now horizontal and the filters are nice and clean unlike the pic.

Here's a pic tho.

http://i121.photobucket.com/albums/o217/chudly/chadstankpics037.jpg

[SpectraPure]

Be sure the probes are both aligned in the same way in their fittings.

Get a gallon of Distilled Water from the store to test the probes. Remove the probes from their push-fittings, rinse with DW and test them by swirling them around in the DW.

They should both read 000 or 001, maybe 002. Adjust to read 001 or just note the difference.

These are not precision devices -- higher accuracy in the single digits can cost several hundred dollars. They could well be within their +/- specs and still be off by a few ppms.

Scott
SpectraPure, Inc.