Request Info on TDS/PH Meters

[HighSeas]

I've been doing some research on PH and TDS meters. Currently, I'm cross-eyed. I want something that can be calibrated and should probably get two separate meters. Does anyone have any suggestions and/or experience with these meters and like what they have?

[billc]

I've used this TDS meter for over a year and it works well if you want to spot check your water solution.
Amazon.com: HM Digital TDS-4TM Meter with Digital Thermometer: Home Improvement
For PH I use a liquid check kit I picked uo at a local hydroponics store.
I've established a baseline for the water I use and now only check the water every month or so.

Bill

[Orchid Whisperer]

Originally Posted by HighSeas

I've been doing some research on PH and TDS meters. Currently, I'm cross-eyed. I want something that can be calibrated and should probably get two separate meters. Does anyone have any suggestions and/or experience with these meters and like what they have?

You are on the right track wishing to get only a meter that can be calibrated. I have seen many low cost "TDS meters", these can probably give you some idea if your electrical conductivity is increasing or decreasing. However without calibration, the number on the readout can't be considered an accurate value.

You may have noticed I said "electrical conductivity" rather than TDS. ALL meters that say they are TDS or salinity meters really are just measuring electrical conductivity (EC), and estimating TDS (or salinity) from the EC number. There are various online calculators that can easily convert from EC to TDS, also.

What I suggest is to get a catalog or go to a website that sells meters for water quality testing (examples would be Ben Meadows, Nasco Science, Hach, or Forestry Suppliers. Nasco offers some budget meters (under $60) that offer calibration (can't vouch for the durability of these meters, though).

The Ben Meadows and Forestry Suppliers sites show professional equipment; prices significantly higher, but you can use the info from those catalogs to check for deals on used equipment off Ebay. Manufacturers I would look for on Ebay deals include Oakton, Hanna Instruments, Hach, Orion (or Thermo Orion). If shopping on Ebay, be sure the meter is complete (includes probe, etc.) and can be used as sold to you.

I have not mentioned pH but you can typically rely on pH test paper, pH monitoring kits, or looking for meters that combine pH and conductivity. The Hach website actually has a stick-type pH, temperature, conductivity, TDS, and salinity meter for $185 (product # 2519800), it can be calibrated, calibration standards sold separately. That is a really good price IMO.

[cbuchman]

I just purchased a pH meter from Amazon:
Etekcity? 0.05 pH High Accuracy Pocket Size pH Meter with ATC(Automatic Temperature Compensation) Backlit Light LCD 0-14 pH Measurement Range, 0.01 Re
Sold by Etekcity

I comes with calibration materials which were easy to use, and the equipment easy to calibrate. I've only had it about 1 week now. So I really can't give you a review. It was about $20 and I opted to buy additional calibration fluid for another $10.

I think for my watering testing needs, this one will work for me.

I didn't get a TDS meter. Can someone explain why I want one and how to use it?

[DavidCampen]

I am happy with this pH meter that I am using.
Oakton EcoTestr pH 2 Waterproof ($63):
Oakton EcoTestr pH 2 Waterproof pH Tester, 0.0 to 14.0 pH Range: Amazon.com: Industrial & Scientific

Before buying that I had purchased a Hanna Instruments pHep pH tester:
Hanna Instruments HI 98107 pHep pH Tester, with +/-0.1 Accuracy: Amazon.com: Industrial & Scientific
This one has a different electrode type and did not work as well as the Oakton and I also quickly broke it.

You should also purchase 2 calibration solutions and a storage solution:
Hanna Instruments HI7004/1L 4.01 pH Buffer Solution, 1L Bottle: Amazon.com: Industrial & Scientific
Hanna Instruments HI7007/1L 7.01 pH Calibration Buffer Solution, 1L Bottle: Amazon.com: Industrial & Scientific
Oakton WD-00653-04 pH/ORP Electrode Storage Solution, 1 Pint Bottle: Amazon.com: Industrial & Scientific

---------- Post added at 07:30 AM ---------- Previous post was at 07:20 AM ----------

Originally Posted by cbuchman

I didn't get a TDS meter. Can someone explain why I want one and how to use it?

A TDS (Total Dissolved Solids) meter measures the electrical conductivity of your water or fertilizer solution and from that it calculates an estimate of the amount of (ionic) material (assumed to be dissolved solids) in the solution. I use one to check that my RO water system is functioning and that my chemical injector is adding the expected amount of fertilizer to my watering solution.

[Orchid Whisperer]

David, that Oakton is about in the price range of the other pH-only meters I saw that I thought would be usable. I agree about the need for the pH buffers and storage solution.

If I did not have access at work to good pH meters, I would probably be using either pH test strips or a pH test kit (e.g. for aquariums/ponds).

@cbuchman, you would mainly want an electrical conductivity or TDS meter to check the dissolved solids in your water, assure the they are not too high. A rule-of-thumb is that TDS should be below about 200 (but it depends on what the dissolved solids are composed of; if dissolved calcium or magnesium sulfate, probably not too bad; if sodium chloride, not good).

[Island Girl]

Not to clog up this thread with unnecessary comments, but Thank You for asking this. I was wondering about the exact same thing! I want something for a reasonable price, but of good, dependable quality. (and also Thanks to Orchid Whisperer, for all the company names you recommended)

[HighSeas]

A TDS (Total Dissolved Solids) meter measures the electrical conductivity of your water or fertilizer solution and from that it calculates an estimate of the amount of (ionic) material (assumed to be dissolved solids) in the solution. I use one to check that my RO water system is functioning and that my chemical injector is adding the expected amount of fertilizer to my watering solution.

I need one for the same reason. I want to make sure my RO system and injector are functioning correctly. The only way to measure their accuracy is with the TDS meter.

Thanks everyone for your suggestions, comments and past experience! You guys are awesome!