TDS Meter Calibration

[Bifferwine]

Anyone with an RODI unit needs a TDS meter to determine if and when their filters need to be changed, and if the unit is working properly. I got my TDS meter off of Ebay probably about 5 years ago for $15. It dawned on me last week that I have never bothered to calibrate it! I should know better -- when I use them for work I have to calibrate them before and after every job.

I bought the correct NaCl calibration fluid off of Ebay ($4.95).
HM Digital 342ppm TDS/NaCl Calibration Solution, 1x3oz - eBay (item 370311918054 end time Feb-24-10 18:04:21 PST)

My TDS was off by about 30 ppm -- luckily it was 30 ppm too high, not too low, so my water was actually cleaner than I had been thinking.

I haven't changed my RODI filters in nearly two years, and the output from it is still less than 10 ppm. Yay!

Don't forget to calibrate all your instruments!

 

[dcantucson]

10ppm in Tucson! Impossible! ? !

 

[Bifferwine]

I know, right?!?! It was bouncing around between 8 and 9.

 

[dcantucson]

Mine is reading 65 after about 5 month old filters. :dunno:

 

[Bifferwine]

Oh wow. This is one reason why I love my cheapo $60 Pure Water Club RODI unit!

 

[Beta173]

Mine runs at 24 before the RODI and 0 afterward. I thought that it was wrong so I calibrated it and it was spot on.

 

[Bifferwine]

Wow your water is excellent then. Here in Tucson, the tap water is anywhere between 400 and 500 :shock:.

 

[SeattleDarko]

Oh wow. This is one reason why I love my cheapo $60 Pure Water Club RODI unit!

Yeah I have seriously been thinking about buying a whole new unit for $100 sell the old one on CL for $50.... but I think its being to lazy how hard is it to change the resin? BTW I don't deal well with sticky stuff and it looks sticky? :shock:

 

[Bifferwine]

When I ordered replacement filters from Pure Water Club, they sent a whole new DI cartridge -- I didn't have to change any resin.

 

[SeattleDarko]

I can probably handle that... I have been dreading it I have some life left on my filters.

thanks

 

[d2mini]

Mine has always 2-4 after the RO and 0 after the DI.

 

[Bifferwine]

Mine has always 2-4 after the RO and 0 after the DI.

I'm happy that I can get in the single digits with Tucson water! Haha.

 

[wontonflip]

Oh wow, I didn't know I was supposed to calibrate my tds :( Guess I should get some calibration fluid. My readings are always at 0 for output...I wonder if I should worry LOL Livestock seem fine. I didn't use it much because I only had a 45g that only needed a gallon or so of top off...but of course I had it running for 2 1/2 days while filling up my 125g. *grr*