Dissolved Oxygen Monitoring

Question 1: Does anyone have an affordable, volunteer-friendly DO meter that you recommend?

Question 2:  Do any of you regularly take DO samples at different depths below the surface? What equipment do you use?

Question 3: Does anyone have an easy to use table for Dissolved Oxygen Percent Saturation at temperatures above 30° Celsius?

Question 1

On Thu, Feb 18, 2010 at 4:05 PM, Kerri Bentkowski wrote:

Dear Water Quality Monitors:

The Buffalo Niagara Riverkeeper is looking to upgrade from Green Lamotte DO tests to DO meters. Does anyone have an affordable, volunteer-friendly DO meter that you recommend?


Kerri Bentkowski Li Citizen Action Coordinator
Buffalo Niagara Riverkeeper
1250 Niagara St.
Buffalo, NY 14221 (716) 852-7483 ext. 11

Responses to Question 1

On Thu, Feb 18, 2010 at 11:48 PM, wrote:

Not cheap but we use YSI 550’s.

Orleans Water Quality Task Force (Cape Cod, MA)


On Fri, Feb 19, 2010 at 8:25 AM, ginger north wrote:

We use Fisherbrand Do meters –they are fairly rugged and fairly stable across a broad temperature range. They cost about $500 each. They are easy to calibrate and the volunteers have found them easy to use.

Ginger North
Citizen Science Coordinator
Delaware Nature Society
302-239-2334 ext. 100


On Fri, Feb 19, 2010 at 9:54 AM, Stepenuck, Kris wrote:


Some of our volunteers use model YSI 550a since the membranes are so easy to replace. But, as someone else noted, they’re not cheap ($925).

Kris Stepenuck
WI Volunteer Stream Monitoring Coordinator / Extension Volunteer Monitoring Network Staff
445 Henry Mall, Rm 202
Madison, WI 53706
608-265-3887 or 608-264-8948


On Fri, Feb 19, 2010 at 11:01 AM, wrote:

To add to that, the probes for these (YSI-550’s, etc.) cannot handle extended exposures to extremely anoxic conditions. We collect a Winkler sample if DO falls below 5.0 mg/L. Otherwise they work great for DO/temp profiles in both marine and freshwater. When we have had to send them out for repair, it is usually because someone used them in bottom waters that had DO readings of less than 1.0 mg/L, or sunk the probe in the mud.

Orleans Water Quality Task Force


From: Linda Green
Sent: Fri, Feb 19, 2010 11:13 am
Subject: RE: [volmonitor] DO Meter Recommendation Wanted

Tho we mostly use LaMotte kits, we have several YSI 55’s (fresh water) and 85’s (salt water). Users need to be sure to calibrate them for altitude and check the membrane for bubbles. We had to add fishing weights to get them to hang straight for lake DO/temperature profiles. We find that we have to have them repaired every 2-3 years at a cost of ~$200 and usually a long time at their repair facility.
Linda Green

Program Director, URI Watershed Watch
Natural Resources Science Department
105 Coastal Institute
1 Greenhouse Road
Kingston, RI 02881-0804
401-874-2905 (v)
401-874-4561 (f)
Project Director, Extension Volunteer Monitoring Network


On Mon, Feb 22, 2010 at 6:43 AM, Sullivan, Christopher wrote:

I’ve used YSI DO200 with a volunteer group I coordinate in Branford. The membranes are screw-on, so easy to change if needed. Calibration is easy and the meter is able to be set for variable salinities. The meter and probe are sold separately and I have had to replace two probes over the past 6 years of use. The probe/cable costs around $250 and the meter has a similar cost.

Good luck, switching to meters from the Lamotte kits we used to use has saved a lot of time on each of our sampling trips. The key is to keep the meters in good condition and calibrated.


Chris Sullivan
Planning & Standards Division
Bureau of Water Protection and Land Reuse
CT Department of Environmental Protection
79 Elm Street
Hartford, CT 06106

Ph: 860-424-3514
Fax: 860-424-4055


On Thu, Feb 18, 2010 at 4:43 PM, Jeremy Williamson wrote:

How affordable? YSI makes a couple of models. I am using the YSI 85, which does multiple parameters, but I think that some of our volunteer groups are using the YSI 55 which just does DO and Temp.

Jeremy Williamson
Water Quality Specialist
Aquatic Invasive Species Coordinator

Land & Water Resources Department
Polk County Wisconsin
100 Polk County Plaza, Suite 120
Balsam Lake, WI 54810
phone 715.485.8639
fax 715.486.8601


On Thu, Feb 18, 2010 at 4:57 PM, Cheryl Nenn wrote:

We use YSI 550A models–mostly b/c that’s the same unit our Dept. of Natural Resources staff uses and we find that if we use their equipment and protocols, that they have more confidence in our data. The units are expensive, and test for DO and temp, but have worked great!

Cheryl Nenn
Milwaukee Riverkeeper
1845 N. Farwell Ave. Suite 100
Milwaukee, WI 53202
(414) 287-0207 ext. 229 (note new extension)
(414) 273-7293 (fax)

Formerly Friends of Milwaukee’s Rivers

Question 2

Date: Mon, 25 Jan 2010 15:01:22 -0500
From: Kim Cressman

Hi everybody,
Volunteers in my program have recently begun using LaMotte kits to take DO measurements. One of the volunteers is interested in profiling the water column by using some sort of contraption to sample at different depths (surface, 0.5 m, 1 m). What sort of contraption is yet to be determined – do any of you regularly take DO samples below the surface? What equipment do you use? We obviously don’t want to introduce oxygen into the sample, and we don’t want to introduce any unnecessary mixing into the water column either.
Any thoughts or tips would be appreciated.
Kim Cressman
Environmental Biologist
City of Cape Coral

Responses to Question 2

Date: Mon, 25 Jan 2010 16:28:44 -0500
From: “Rathbun, Joseph (DEQ)”

Look at the LaMotte DO Water Sampler – p. 337 in the Forestry Suppliers catalog #60. $101


Date: Mon, 25 Jan 2010 16:31:14 -0500
From: Ann Schenk

The 0.5 m is easy — hold sample bottle upside down while immersing it to 1/2 meter, turn right-side up and cap while holding it at that depth. Deeper than that, and you are looking at Kemmerrer, Van Dorn or Niskin bottles, or a pump and hose. The sampling bottles run in the $400-$600 price range to buy, any they can be rented from several companies.
See link below for more details on selection and usage of sampling bottles.

The pump and hose option is generally home-made. A 12-V bilge pump and garden hose is easy if working from a boat, but not practical if wading. Batteries are heavy and dangerous in that situation. Have not tried “fountain” or large aquarium pumps as they usually need house power, which is generally not practical.
Ann Schenk


Date: Mon, 25 Jan 2010 17:00:07 -0500
From: URI Watershed Watch

The most recent Volunteer Monitor newsletter included directions for making a variety of water samplers, included discrete depth samplers for dissolved oxygen. Please see: to download a pdf.
Our program uses the LaMotte Water Sampling Bottle (3-0026) for sampling as 1 – 20 meters with good success. They cost about $170, and you have to add your own calibrated line and weights, but they’ve been real work horses for us!

Good luck!
Elizabeth Herron
URI Watershed Watch
Phone: 401-874-4552
Fax: 401-874-4561


Date: Mon, 25 Jan 2010 14:08:02 -0800
From: “Williams, Gene”

We have had volunteers doing DO profiles in lakes using LaMotte kits and DO samplers similar to the one Joseph noted or using Van Dorn-type samplers. We use the student water samplers from Aquatic Research Instruments ( (about $200) , but they also make the DO samplers.
I am inserting an excerpt from the monitoring procedures in our QAPP (24 KB pdf file) that describes in detail how to use the DO sampler or Van Dorn vertical sampler to take DO measurements at depth being careful not to introduce air into the samples. It’s way more detailed on all the testing steps than you need, but you can find the description of using the samplers.
I hope this example from our program helps.
Gene Williams
Snohomish County Public Works
Surface Water Management
3000 Rockefeller Avenue, M/S 607
Everett, WA 98201-4046
(425) 388-3464 x4563


Date: Mon, 25 Jan 2010 17:57:15 -0800 (PST)
From: Revital Katznelson

We made widespread use of the upright sampling apparatus in California; this apparatus holds the 60-ml DO bottle inside a bigger chamber and it gets flushed with several volumes of water before the sample is used for the Winkler titration. There are several commercial models you can choose from (thanks, all of you who responded), and you can also build one yourself based on the same principle. You may find a useful drawing in our SOP in the Clean Water Team Guidance Compendium, at
Here is another option:
Way back in the 1980s I rigged a syringe-pump apparatus, made of a 60ml syringe, tubing, and a three-way stopcock, for collection of water samples at defined depths below the water surface without contact with air. I used the samples for analyses of dissolved oxygen, sulfides, and other water quality characteristics. It works really well for depths up to 3 meters. I built it again in the 1990s with my colleague, and the instructions were published as SOP (Construction and Use of a Syringe Pump Apparatus) in the Clean Water Team Guidance Compendium, at
Good luck,
Revital Katznelson, Ph.D.
Environmental Scientist
Berkeley, California
510 406 8514


Date: Tue, 26 Jan 2010 12:39:07 -0500

We use direct reading instruments like a YSI, and take measurements at different depths (profile) for most of our volunteer monitoring efforts in both marine, and freshwater lakes and ponds. You can also collect a Winkler sample, but it requires volunteers to fix the sample in the field with small chemical packets, and normally a certified lab does the analyses which costs money. When we do collect DO samples (Winkler bottles), we use a Niskin sample bottle for collection at different depths. There is a special procedure used when collecting a Winkler sample so that extra oxygen is not introduced. However, based on my own experience with volunteer monitoring efforts, the direct reading instrument is the way to go. This also allows you to collect the temperature data you need for your DO/temp profile. We only collect a Winkler sample when the DO reading using the YSI is below 5.0 mg/L.

There are some excellent volunteer monitoring programs and technical resources available in Southwest Florida. I attended a great conference in Punta Gorda about 6 years ago. I remember Port Charlotte had a group, and so did the Peace River. SW Florida has a good water resources group too. I am sure there is a very large water quality network available to you. Just search the Net. The folks at the Ding Darling (national wildlife preserve) on Sanibel can probably help you also. I live in MA on Cape Cod, but just arrived on Sanibel yesterday where I will be for 2 months, so if I can help you more, please feel free to contact me.

Orleans Water Quality Task Force
Orleans, MA (Cape Cod)

Question 3

Date: Wed, 30 Jul 2008 12:54:06 -0400
From: Lauren Webster
Subject: [volmonitor] Dissolved Oxygen Percent Saturation

Hi all,

I began a citizen water quality monitoring program earlier this year. The participants use basic sampling kits from LaMotte. Now that it has gotten warmer, testers are reading water temperatures above 30° Celsius. Does anyone have an easy to use table for Dissolved Oxygen Percent Saturation at temperatures above 30° Celsius?


Lauren Webster

Restoration Coordinator
Patuxent Riverkeeper
(301) 249-8200 ext 6

Responses to Question 3

Date: Wed, 30 Jul 2008 11:14:35 -0600
From: Claire Foster
Subject: Re: [volmonitor] Dissolved Oxygen Percent Saturation

Hi Lauren,
Water on the Web has instructions for calculating percent saturation for dissolved oxygen using a formula – you could certainly create an easy to use table that goes as high as you need it using these directions. Here’s the link:
The formula itself is a little daunting, but if you paste the excel version into a spreadsheet and fill it in, it’s not hard at all. If you don’t want to correct for altitude, you can just enter 1 for the atmospheric pressure.

Hope that’s helpful!

Claire Foster


Date: Wed, 30 Jul 2008 12:36:44 -0500
From: Chris Riggert

I created an Excel sheet that lists DO up to 15 ppm, and water temps to 39 C (makes a nice rectangular box, ha)…it also has the formula on the bottom if needed. It went over so well we ended up incorporating it into our training manuals. I would be happy to forward it to whomever wants one (can’t attach things to the listserv).

Editor’s note: Chris sent us two files to post online. Chris pointed out that they show basically the same thing, just in slightly different format. They follow:

DO Conversion Table (11 KB pdf file)

DO Conversion Table 2 (10 KB pdf file)


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



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