TDS Meter Calibration

wags · 10-14-2005, 11:14 AM

I have asked how to do this before and I know they sell the calibration solutions. Anyone know where to find them locally? Can't justify mail order for a $2.00 item alone but with gas prices it might be cheaper.

Also, I read somewhere (and now I can't remember where) that you could calibrate with distilled water like you can buy in the gallon jugs at Cub/Rainbow... Anyone ever try this?

FastFish720 · 10-14-2005, 11:18 AM

Do you know where you got TDS meter from?

wags · 10-14-2005, 11:25 AM

Its the same as the Hanna TDS 1 pen meter I've seen on line and has not been calibrated in probably over 2 years. Since it hasn't been used in so long I'm not sure I want to trust it check out my RO/DI output. I'd feel better knowing I calibrated it.

David Grigor · 10-14-2005, 11:49 AM

Perhaps, just comparing results with someone else's meter would suffice. Really, IMO: I doesn't have to be exact, only relative to a new set of filters so you can get an idea with they start to go south....

wags · 10-14-2005, 01:47 PM

David - I agree with that philosophy. Just wondering how "bad" it might be to calibrate with the distilled water from the grocery store.

thegrimreefer · 10-14-2005, 02:04 PM

I would still consider calibrating against at least one other solution. Besides, it's more fun! Consider:
Someone asks you to calibrate the spedometer in their Enzo Ferrari. They have the car, and you, carted out to the speedway. You look, and see that the spedometer ranges from 0 to 250 MPH. With the engine off and the parking brake set, you carefully adjust the spedomoter to accurately read: Zero.
Honestly, are you REALLY satisfied with calibrating that instrument at only one point in its range?
I didn't think so.
--
Ron

reefmyster · 10-15-2005, 03:37 AM

IMO The enzo is sweet, but if you are sitting at a dead stop and it reads zero why would you bother. The TDS meter is just like horseshoes and hand grenades. Moniter your RO water and when the TDS rises enough its time to replace something.

Besides no 85 year old cares how fast they they are going in their enzo. 40 in a 70 is about normal isnt it?

thegrimreefer · 10-15-2005, 04:05 AM

The overall idea, of course, is that knowing your instrument is accurate at only one point in its range tells you fairly little about how it's working in general. Particularly if that one point is a point you don't really care about.

Alero · 10-15-2005, 06:53 AM

I just got my new RO system (aquasafe) and TDS meter a few weeks back. The TDS said it was calibrated. I checked TDS from my RO and it was at 3ppm, Then I checked a few days later and then I am getting readings in the 50ppm. So I am assuming I don't have to change any of the filters yet since it so new. So feel I need to recalibrate mine also.

I am in the same boat as wondering one what you can use.

Loverotties · 10-15-2005, 07:49 AM

I know the distilled water from walmart is zero TDS.

Floppy · 10-15-2005, 09:20 AM

I think i've read an article by Randy Farley that calibration of tds meters isn't always needed.

He basically said that if you are just testing pure water to get a reading of "0" it isn't all that important to calibrate. If you get a reading of 0 while it is dry(out of water) and obviously no disolved solids. That it is pretty much on for pure water testing. Now, if you get a reading of 55 while out of water, something is up.

Take that for what its worth.

Floppy · 10-15-2005, 02:44 PM

Yup I've confirmed my thinking with Randy;

http://reefcentral.com/forums/showth...30#post5909030