Calibrating TDS meter?

[fishman1069]

Does it have to be done? I have had my RO/DI unit for 2 years along with my TDS meter. I got it of ebay, brand new. Its a TDS EZ from HM Digital. On the back it says " calibrate with NaCl. I dont have the instructions, so I dont know how to do it. I see a lil hole under the NaCl, but I dont know what the tds is on sodium chloride? The meter is reading 1 ppm and I havent changed my filter since I set up the unit! Im definitely getting phosphates in my tank but that can be coming from feeding also. Any advice would be much appreciated.

 

[Jkedra]

I have the same meter...I think it should be calibrated...It started to give me inaccurate readings so I re calibrated and it works fine.

 

[fishman1069]

How did you recalibrate it?

 

[Jkedra]

I havent used my TDS meter in a loong time...but do you have the NaCl solution?
The meter has a specific calibration solution...
If not, heres the link: http://www.tdsmeter.com/

I know one thing for sure...If the meter is used daily, it should be calibrated every week...If you use it less than daily, then calibrate it every two to three weeks.

Also, A good tip for calibration straight from the website:
"HM Digital products are calibrated with a 342 PPM NaCl or 1413 ?S solution. This is suitable for most applications. However, if you are measuring samples that are consistently over 1000 PPM, it is recommended to recalibrate the meter for that specific application."

But its hard to tell how many times the previous owner used it.

Here are the instructions in detail for calibration:
http://www.tdsmeter.com/TDS_Meter_Calibration_Instructions.pdf

 

[fishman1069]

Cool Thanx man I appreciate it. Russ just sent me a pm with the link to get the solution. Im gonna order when I get home from work today. Man I hope Im not that much off. I havent calibrated this thing in 2 years!!