Total Dissolved Solids Meters

Question 1: I’m looking at Total Dissolved Solids portable meters and wondered what experience folks have had with them as far as durability, etc.

Question 2: Does anyone have any experience and advise on which total dissolved solids meters are the best ones to use?

Question 1

Date: Wed, 16 Mar 2005 13:18:00 -0600
From: Steven Witmer
Subject: [volmonitor] Total Dissolved Solids – meters

Hello all,

I’m looking at Total Dissolved Solids portable (preferably “pocket”) meters and wondered what experience folks have had with them as far as durability, cost, accuracy, etc. I’m looking for something that is inexpensive (of course) but yet accurate enough to be worthwhile and durable enough for field use. I’ve seen price ranges from as low as around $20, while others are more like ten times that and everything in between. I’d hate to go cheap and end up with something that won’t serve it’s purpose or last more than a week, but on the other hand I’d rather not spend a lot of money if there is something cheaper that will do just about as well.

Feel free to respond to the list – I’m sure others out there would be interested as well. If there are any comments on field meters generally regardless of parameter, I’d be happy to see those, too.

Steven Witmer

Responses to Question 1

Date: Thu, 17 Mar 2005 11:03:38 -0500
From: Ginger North
Subject: RE: [volmonitor] Total Dissolved Solids – meters

Steve – We have used several different conductivity meters over the years & the ones we are using now are easy to use, reliable, not as accurate as some but sturdy in field conditions & wide temperature ranges. They are Oakton brand & come in Total Dissolved Solids readout as well as conductivity & for an extra $20 you can get temperature readout as well. The ones we use are about $55 & handheld “pocket” meters. We have been only using them for the past 2 years so I am not sure about their lifespan as yet. Some of the meters we have used in the past only have a limited lifespan – 3 or 4 years. At $55 we can afford to replace them after a few years however. They only read in increments of 10uS for the low range (0-1990uS) which is plenty sensitive for our purposes. Oakton ECTestr Low is model we use. The TDS model is called TDStestr Low (0-1990ppm)resolution is 10ppm & TDSTestr High (0-10ppt).
Ginger North
Stream Watch Coordinator
Delaware Nature Society
Fax 302-239-2473


Date: Tue, 22 Mar 2005 13:51:07 -0600
From: Steven Witmer
Subject: [volmonitor] TDS meter response

I thought I’d share the results of my query to the group for TDS portable meters. I got several responses on and off the list, and all of them pointed me toward Oakton low-range models, and most recommended the waterproof models especially. Cost on them (based on the responses and from online browsing I’ve done) runs around $60 or so.

My thanks to everyone who shared their comments!

Steven Witmer

Question 2

On Wed, Feb 10, 2010 at 11:16 AM, Wilderman, Candie wrote:

We are currently developing a protocol for volunteer monitors to be watchdogs for impact from Marcellus shale gas development activities in PA. As part of that protocol, we would like to measure Total Dissolved Solids, using one of the many small TDS meters (which actually measure conductivity) that are now on the market.

Does anyone have any experience and advise on which ones are the best ones to use, considering both accuracy/precision and ease of calibration/use? We would like to spend less than $100 per meter. What would be the most important features to consider in making this choice?

Any advise would be greatly appreciated! If folks would like, I’d be happy to compile responses and post.

Candie Wilderman
Founder and Science Director
Alliance for Aquatic Resource Monitoring (ALLARM)
Dickinson College
Carlisle, PA 17011

Responses to Question 2

On Wed, Feb 10, 2010 at 12:36 PM, Chris Riggert wrote:

Hi Candie,

We have used a couple of TDS/conductivity pens over the years with the MO Stream Team’s VWQM. The first pen was a ‘TDS’ pen, but as you accurately surmised, it was really measuring conductivity and doing a mathematical calculation to provide the reading. About 10 years ago we switched to the Pocket Pal Conductivity Tester from Hach (# 2686601, $67.89). When these pens worked, they worked very well, and were relatively inexpensive. However:
– they were a bear to calibrate because of the placement of the calibration screw (on the back of the pen…opposite the LCD readout),
– they were very jumpy (couldn’t have ANY metal around, including jewelry, notebook rings, etc.),
– and overall, we ended up replacing a lot of ‘bad’ pens.
– Additionally, despite claims, they were not waterproof, so if submerged too deeply into the water…well, you can guess how well they functioned after that.

With this in mind we began testing other products that were both affordable, but still met our acceptability limits. About 5-6 years ago, we decided to switch to the Oakton Conductivity Tester from Hach (#2845500, $81.39). Yes, they run about $15 more than the Pocket Pal model, but they are a much better pen.
– They are MUCH easier to calibrate (push buttons under the battery cap),
– has a ‘hold’ button allowing you to take your reading and hold it making it easier to read without standing on your head in the water,
– has an auto-shutoff (saves tons on replacement batteries),
– are waterproof (with rubber O-rings preventing water from entering circuitry),
– has a replaceable tip/probe preventing the replacement of the entire pen (Hach # 2845900, $51.25).
– it comes in its own plastic box that you can put a little silica pack in during storage to help prevent rusting of the probes.
– One thing to keep in mind is that the probes are coated with a thin layer of oil to prevent rusting during storage, so this must be cleaned off prior to using (easily done with rubbing alcohol and a cotton ball).

The long and short of it is we are happy to have made the switch to the Oakton pens. They test well, are ‘relatively’ inexpensive, are much easier to calibrate and use, I believe we are getting better data because of it, and saving money in the long run b/c we are replacing fewer pens.

Hope this helps!!

Christopher M. Riggert
Stream Team Program
Volunteer Water Quality Monitoring Coordinator
Missouri Department of Conservation
P.O. Box 180
2901 W. Truman Blvd.
Jefferson City, MO 65102-0180
Phone: (573) 522-4115 ext. 3167
Fax: (573) 526-0990


On Fri, Feb 12, 2010 at 10:49 AM, ginger north wrote:

Candie – We too have been using the Oakton TDSTestr for about 7 or 8 years – different models as they update them we now use the model #11 and we have had no problems with them at all. They are very easy to use and very stable as Chris mentioned. So I would second that recommendation.
Ginger North
Science Science Coordinator
Delaware Nature Society
PO Box 700
Hockessin, DE 19707
302-239-2334 ext. 100

On Fri, Feb 12, 2010 at 3:27 PM, Revital Katznelson wrote:

I also found that the Oakton conductivity and TDS meters worked well. However, one of their models had a very thick layer of plastic around the thermistor, and the temperature (which affects the temperature-compensated reading) took a long time to equilibrate. As I recall, I added a sentence about this to the Clean Water Team’s SOP- (available at )

510 406 8514

From: Bonani Madikizela
To: “” , ‘Volunteer water monitoring’
Date: Thu, 11 Feb 2010 08:18:32 +0200
Subject: FW: Somerset Water Kits

Good day volunteers !

In South Africa I ‘m busy implementing a voluntary monitoring programme, called Adopt a River. Indeed I ‘m looking at simply tools for the public participation and school kids. I haveMalcom Beech of Somerset Water Kits. I strongly believe that he can answer your questions regarding electrical conductivity, which can also be broadly calculated to estimate TDS.

Enjoy your fun days in the field, we do so in South Africa !



Mr Bonani Madikizela
Research Manager
Water Research Commission
Private Bag X03, Gezina, 0031, South Africa
Tel: +27 12 330 9021
Fax: +27 12 331 2565
Cell: +0832907238

From: Zagry Scholtz
Sent: Wednesday, February 03, 2010 7:17 PM
To: Bonani Madikizela
Subject: FW: Somerset Water Kits


From: Malcom Beech []
Sent: 03 February 2010 05:40 PM
To: Zagry Scholtz
Subject: Somerset Water Kits

Dear Zagry


Thank you for your valued enquiry today regarding the water testing kits we supply.

We have shipped off to you a Microlife Water Quality Testing Kit plus a Microlife Water Field Kit, to assist you in establishing which kit would better serve your needs for this project.

Attached please find our catalogue (1.3 MB odf file), in which I kindly refer you to page 19 for details on the two kits.

I look forward to your feedback.

With kind regards


Malcolm Beech
Managing Director
Somerset Educational (Pty) Ltd
Tel : 042 – 243 2030
Fax : 042 – 243 2746
Cell : 082 314 3567


Volunteer Monitoring Trends


On Jan 17, 2005, at 12:30 AM, Eleanor Ely wrote:
Dear friends:
Today I got a call from a writer who wanted quick and easy answers to large and difficult questions about volunteer monitoring. I was little annoyed that he seemed to be trying to throw something together at the last minute with a minimum of effort. But at the same time I felt bad that I couldn’t answer his questions. He was mainly looking for “news” — specifically, he wanted to know what’s new in the past decade. Is volunteer monitoring “growing”? Are there more programs, or more volunteers? What are the latest trends? (More centralization? More collaboration?) What new volunteer monitoring equipment or methods have been developed in the past decade? I wasn’t very helpful, and I tried to explain that no one really knows the answers to some of these questions — that it would take a lot of research and time to find out. But after I got off the phone two ideas occurred to me.

The first was that in some ways he was asking the wrong questions. He was looking for what’s new, what’s different. And I started thinking that a lot of the value of monitoring comes from what is NOT new. The fact that a lot of groups celebrated their 10th, 20th, or even 30th anniversary last year is probably more important than how many new groups formed that year or what new technologies were developed. The fact that some volunteers celebrated their 5th, 10th, or 15th anniversary with a monitoring program is probably more important than how many new volunteers the program recruited. In a sense, what you want to see in a volunteer monitoring program is the “same old same old” — same volunteers, same methods and parameters, and even (if your water body is healthy) the same results. And yet, as has been noted before, that sort of thing is not glamorous and sexy; it’s not “news.” Which is one of the things that makes it hard to convince policymakers and funders of the value of long-term monitoring.

But after thinking all that, I also decided that there probably IS some “news,” and that was when I got my second idea — the idea of asking people on this listserv for their views. I would love to hear your comments on my preliminary thoughts (see below) about possible “trends” in the last decade.

– Are there more programs? Since there hasn’t been a survey since 1998, I don’t think anyone knows the answer. My impression is that budget cuts have taken their toll on volunteer monitoring and that some groups have gone under. At the same time, though, new groups have also formed. But I don’t have a clear sense that there has been net growth. What do others think? – Speaking of budget cuts, for the last 15 years I’ve been hearing about the “slashing” of agency and volunteer funding, but my gut feeling is that it’s more serious now. I think volunteer groups are responding in various ways — looking for new sources of support, and at the same time tightening belts more than before. And while the “positive spin” might be that volunteer groups are finding new partners and that agencies are more open to volunteer
data (since they can’t afford to collect their own), my sense is that on the whole volunteer monitoring is suffering from a decline in funding — that programs are having to cut back their activities, reduce the number of volunteers, and in some cases close down operations altogether. I’m hoping that some of you can convince me that this view is overly bleak. – Is there more centralization and/or collaboration? I know that monitoring programs are always forming new partnerships, trying to coordinate with other groups in the watershed, etc. Is there more of that now than 10 years ago? I’m not sure. However, I think I would feel pretty safe in saying that there is more data sharing, partly because nowadays groups are posting their data on the Internet, which wasn’t happening 10 years ago.

– Are volunteer monitoring data being more accepted by agencies, researchers, etc.? Certainly we would all like to think so! Based on
”anecdotal evidence,” I would answer this question in the affirmative. But maybe that’s because I tend to hear the good news — people are more interested in telling the world about their success than about their frustration. What do others think — is there a genuine trend toward more acceptance of volunteer monitoring data?

– New developments in methodology and equipment? The writer who called me had glanced at the most recent VM and noticed the picture of the horizontal clarity tube, so he suggested that “horizontal monitoring” might be a hot new trend. No, I said (mentally picturing monitors lying down next to their water bodies), I didn’t think horizontal monitoring would be a good example of a new trend, but perhaps the clarity tube itself (vertical version) might qualify as an important new piece of equipment introduced in the past decade. Now I’m trying to think of other examples. What about the relatively new simplified methods for monitoring coliforms and E. coli, which are gaining more and more widespread use? Any other ideas?

– Another new trend, I think, is online data entry. Would anyone like to comment on the significance of this?

Thanks, everyone, for your patience in reading all this. I’m looking forward to receiving some interesting feedback, and perhaps publishing a summary of responses in the next issue of the newsletter. I think in this case it might be useful to post responses to the entire listserv. Maybe we can get a dialog going.

Eleanor Ely
Editor, The Volunteer Monitor Newsletter
50 Benton Avenue
San Francisco, CA 94112


Date: Mon, 17 Jan 2005 07:17:14 -0800 (PST)
From: David J Wilson
Subject: Re: [volmonitor] ideas needed — volunteer monitoring “trends”

Dear Ellie,

(1) I agree with you that it is rather stupid for someone to attempt to throw together on short notice a picture of the current state of affairs in volunteer monitoring. Such an article is likely to be loaded with errors and may do more harm than good. Sorry.

(2) Given that sediment is a major water quality problem nationally, the appearance on the scene of cheap turbidity/transparency tubes is certainly significant. This is strongly reinforced by Tim Diehl’s (USGS, Nashville office) work showing the excellent correlation between transparencies and nephelometric turbidimeter measurements. The cost of a turbidity tube is sufficiently small that a volunteer group can pay for a few of these out of its own pockets, as was done by the Harpeth River Watershed Association in TN and as we are doing in the Huron River Watershed Council in MI. The horizontal tube is an interesting extension of the turbidity tube technique; we have not, however, needed it in any of our turbidity/TSS work on the Harpeth and the Huron Rivers, and I do not expect that it will be a major player.

(3) Most states are having extreme budgetary difficulties; the enormous federal government is piling up staggering budget deficits; and the present federal administration has shown itself to be extremely hostile to any and all environmental concerns. I therefore think that we shall see volunteer monitoring groups focussing on getting the most bang for their own bucks, rather than wasting time hustling for non-existent state and federal dollars. Sediment studies, studies that can be done with field test kits (DO, phosphate, nitrate, pH), visual assessments, bank erosion monitoring, and benthic macroinvertebrate studies are all examples of monitoring that can be done on a low budget–at a price a volunteer group can raise on its own without government assistance. I note that this was the way volunteer monitoring started out before it even had a name; concerned and outraged citizens’ groups raised their own money and did! their own thing with the governments dragging their feet at every level. See, for example, what was done by volunteer groups in Rochester, NY, and St. Louis back in the 60’s. Yes, it is nice to be able to get government money. It is very nice to be able to have the support and guidance of paid professional staff. But this is not necessary in order for us to do what needs to be done, as was established back in the 60’s.

(4) THE crucial, essential element in effective volunteer monitoring is not government money, but the presence of a small cadre, either professional staff or volunteer people, who are dedicated and who are knowledgeable about the techniques and procedures to be used and can train the other volunteers. If we cannot hire professional staff for this, then it will be necessary for people with professional training in chemistry, biology, etc., to come forward to do it, as we did back in the 60’s and 70’s. See, for example, Proc. Rochester Acad. Sci., Oct. 1982 special edition, Studies of Pollution Control in a Lakefront Community 1964-1981. Government money certainly makes things easier and faster by allowing the use of full-time professional staff (bless them!) and the running of high-ticket projects. But government money is not essential. Dedicated, concerned, angry people are essential.

With best regards,

Dave Wilson


Date: Tue, 18 Jan 2005 08:53:24 -0500
From: Nancy Hadley
Subject: Re: [volmonitor] ideas needed — volunteer monitoring “trends”
To: Volunteer water monitoring

I think online data entry is one of the biggest advances. It not only gets the data into your database faster (although perhaps complicating the QA/QC) but it gives the volunteers an additional sense of responsibility and ownership. That is what keeps volunteers in the program. If you just monitor and the data goes away, you are disconnected. the connection is key.

As to new equipment, we are using a dissolved oxygen kit by Chemets which I think is awesome. However, I dont have the sense anybody else is using it. I know it is not yet EPA approved so tht may be why. I would be interested in hearing from anybody who has tried this kit and what they thought.

Nancy Hadley
South Carolina Oyster Restoration and Enhancement Program
Marine Resources Research Institute
South Carolina Department of Natural Resources
PO Box 12559
217 Fort Johnson Road
Charleston, SC 29412
(843) 953-9841
(843) 953-9820 (fax)



Water Quality Test Kits


Date: Thu, 22 Dec 2005 17:30:47 -0500
From: Jerry Schoen
Subject: [volmonitor] Water testing kits

Hello all,
I am trying to put together a list of water testing kits for a variety of WQ indicators – with notation regarding whether kits have received EPA approval. I would appreciate hearing from you about any kits your volunteer monitoring group uses or is familiar with. Any addtional information about EPA approval, either as an approved SOP or by virtue of an approved QAPP wherein the kit is used for a particular WQ indicator, would be appreciated.

Jerry Schoen
Blaisdell House
UMass Amherst MA 01003

545-2304 Fax


Date: Fri, 23 Dec 2005 07:04:00 -0500
From: Sidney Post
Subject: RE: [volmonitor] Water testing kits


We utilize HACH and LaMotte kits and have done so for the past sixteen years. As far as EPA approval; I’m not sure? we use several of the HACH kits with our utility water quality sampling program (I’ll have to look into this). We have strict training in how to use both HACH and LaMotte kits along with strict QA and QC. Hope this helps in some way.

Sidney Post

Watershed Action Team Coordinator
Sidney Post
624 Filter Plant Drive
Fayetteville, NC 28301


Date: Fri, 23 Dec 2005 09:28:11 -0500 (EST)
Subject: RE: [volmonitor] Water testing kits

I would suggest containing the manufacturer. TO my knowledge some methods have EPA Approval, but these methods tend to require higher end equipment. Also, even with “strict” QC it is still possible to see variation in the 10 to 20% range.

Brian Oram
Wilkes Univesity
Center for Environmental Quality

We tend to use field kits as a screening tool only. We also like to use water quality meters: such as YSI and others. The meters can be calibrated by one person and typically the meters have internal
diagnostics. It is also important to look at detection limit. For many tests, the detection limit is not low enough or it is necessary to digest a sample for matrix interference.


Date: Fri, 23 Dec 2005 09:49:29 -0500
From: Geoff Dates
Subject: Re: [volmonitor] Water testing kits


It’s been a few years since I looked at this issue, so I hope someone from EPA can clarify. What I discovered is that “EPA-approved” is a term that was used rather loosely by kit manufacturers. Most often, the kits hadn’t gone through any formal review process, but simply were based on an EPA approved method. The most helpful response would address your last sentence by defining the various levels of approval and how one finds out the status of a particular kit.

A great resource is the National Environmental Methods Index (NEMI)web site ( Some verbage from the web site:
NEMI is being developed under the direction of the Methods and Data Comparability Board, a partnership of water-quality experts from Federal agencies, States, Tribes, municipalities, industry, and private organizations. The Methods Board is chartered under the National Water Quality Monitoring Council. NEMI makes finding approved methods a much easier task by allowing the user to simply select the pollutant and regulation of interest. A list of the approved methods, with all relevant modifications required by CFR footnotes will be quickly generated. Furthermore, you can download the approved version of publicly available methods with a single mouse click.

Another source is EPA’s Office of Research and Development’s Environmental Technology Verification (ETV) Program develops testing protocols and verifies the performance of innovative technologies that have the potential to improve protection of human health and the environment.

Good luck!


Geoff Dates
River Watch Program Director
River Network
Home Office:
231 24D Heritage Condos
Woodstock, VT 05091
802-457-9808 w & h
River Network Web Site:


Date: Mon, 02 Jan 2006 15:00:07 -0500
From: Linda Green
Subject: RE: [volmonitor] Water testing kits

Hi Jerry and vol mon folks,


This isn’t exactly what you are looking for, but may help. At we have an annotated list of suppliers of water monitoring equipment used by vol mon groups.

URI Watershed Watch has a newly EPA-approved QAPP for our field monitoring program at We use LaMotte kits for dissolved oxygen (#5860) and for salinity (#7459). The appendices for that QAPP with the specific procedures (SOP’s) haven’t been posted yet.

As Geoff says in his response to your posting, NEMI National Environmental Methods Index (NEMI)web site ( is a good resource for methods, but it isn’t comprehensive and doesn’t have a lot of of vol mon methods, particularly kits. The methods on the site were nominated by someone and then thoroughly reviewed by selected members of the Methods and Data Comparability Board, which is a very active and fairly autonomous work group of the National Water Quality Monitoring Council. (PS they would love to have some vol mon coordinator members)

Happy New Year to all!

Linda Green

URI Cooperative Extension Water Quality
Department of Natural Resources Science
1 Greenhouse Road
Kingston, RI 02881-0804


Date: Tue, 03 Jan 2006 19:09:23 -0500
From: “Picotte, Amy”
Subject: RE: [volmonitor] Water testing kits

Hi Jerry and other lovely volunteer monitoring people, I don’t have a lot of experience using kits, but through the Project WET program the HACH company has developed several kits for vol. monitors, which I have heard are fabulous. The Healthy Water, Healthy People (Project WET) site will have the info at

Also, in Appendix D of the “Vermont Volunteer Surface Water Monitoring Guide” there is a listing of water testing kit vendors.

Hope this helps some. Happy New Year.

Amy Picotte
Environmental Analyst
DEC-Water Quality Division
103 S. Main St.
Waterbury, VT 05671-0408
Tel. 802-241-3789
fax. 802-241-4537