TDS Probe - strange results

[SueAndHerZoo]

Hi there.
I just purchased one of those nifty $65 probes that allows you to test your temperature, salinity and TDS by dipping the tip in the water and pressing a button. It works really well, EXCEPT it's showing me something strange. I have tested my tap water and get a reading I would expect, I then check the RO/DI water just as it comes out of the spigot, and I get .2, but when I check the 30 gallon Brute bucket of RO/DI water it's always off the charts "HIGH". The Brute bucket is brand new (rinsed well, of course) so last night we dumped the 30 gallons of water out and started a fresh batch. I just went down and checked the few gallons of water that are in the Brute bucket and it reads "High". If I take a cupful of that water out and test it, I got .3. If I test the small amount of water that's in the Brute bucket, it's "High". We keep the bucket tightly covered so I'm not sure why this is happening. Any thoughts?
Sue

 

[lapin]

If I understand this you are testing the same water. In bucket= high / out of bucket 0.3
Sounds like your tester is effected by light.

 

[SueAndHerZoo]

Wow.... I would have never thought of that! Now I need to go do some research to see if anyone else has noticed light affecting the results. I'm not sure why it would, but anything is possible and that would certainly explain the strange variation in results. Maybe I'll take a small cup of the water into a dark closet!

 

[lapin]

Another closet drinker ? )))))))

 

[SueAndHerZoo]

Another closet drinker ? )))))))

SSSHHH! ;Wacky (Quiet, or I won't share!)
Sue

 

[SueAndHerZoo]

OK, that didn't work. I've been taking cups of the RO/DI water into all different types of lighting and am still getting strange results. Next thing I'm going to test is perhaps temperature of the water? Hopefully when I get home tonight.
Sue