Are you serious about water testing accuracy? Hach DR-2000

jrpark22000

jrpark22000

Premium member
I’m a “bit” obsessive. I wanted to share my results and equipment for anyone else who is as critical of hobby grade tests. It wasn’t cheap but relatively it is.

I picked up a used Hach Drel spectrophotometer kit on ebay for $360 shipped.
http://www.hach.com/dr-2000-spectrophotometer/product?id=7640439022
http://www.hach.com/dr-2000-spectrophotometer/product-downloads?id=7640439022

The Drel kit Specs:
DR 2000 spectrophotometer (digital LCD output)
pH meter (I don’t have a need for it)
conductivity meter (I use it for a 3rd backup)
digital titrator
Soil testing kit (not included in the Drel kit, but came in the ebay auction)
Carry cases
Many outdated reagents
2 sets matched sample cells
Flasks, DO sample bottle, grad cylinders, etc, etc.

All of the extra goodies do add up quickly if purchased separately. I did replace the halogen bulb but it was done prematurely. The manuals are all available on Hach.com as well as new reagents. I picked up reagents for alk, CA/MG hardness, nitrite, nitrate, ammonia, p04, iron(just for curiosity), iodine(also does bromine and chlorine) and pH cal pillows. All told a few hundred more but you get 100 tests for most of those so price per test is cheap. There are several more test this kit can do for saltwater but I don’t feel the need to monitor for them today.

I do use API CA and ALK for my frequent tests as well as salifert for Mg. If done properly they do give good repeatable results that are quick and easy. That said, the test kits for the other parameters are a crap shoot. For all of them you must have good lab practices to get repeatable results including using the same light source to account for color shift. Even then you still estimate the color compared to a card which takes repetition to develop an eye for it. When you factor in the manufacturers stated testing variance for each kit with most hobbyist testing procedures, it leaves little wonder why many people can’t trust their results.




Tests I use for the above Hach kit:

ALK is titration but with the digital titrator it is easy
Method 8203, not much else to comment on, it easy

CA/MG hardness takes serial dilution for the DR 2000, which adds to the complexity and chance of error
I’m still debating about switching to the EDTA titrator method 8329 (reagent 24487-00) as it is easier than the serial dilution for similar amount of testing variance
Calmagite colorimetric method 8030, test 225 & 220

Nitrite is a single reagent pillow but takes 15 minutes to develop
Diazotization method 8507, test 371

Nitrate uses 2 pillows (only 50 tests per bag) and takes 7 minutes to develop
Cadmium reduction method 8171, MidRange test 353 but reagent also works for HiRange
Nitrite is a factor in the nitrate test results but typically is very small factor

Ammonia nessler or salicylate (I went nessler due to reagent cost but should have went salicylate for ease and ability to use w/ ammonia-locks)
Nessler method 8038, test 380

Po4 use one pillow and 2 minutes to develop
Ascorbic method 8048, test 490
Dead on repeatable results down to .05, any less would require I set aside specific testing equipment (cells, grad cylinder, etc) for just this test.

Iron Total uses one pillow and 3 minutes to develop
FerroVer Method 8008, test 265
Will most likely result in 0.00 results for most tanks

Iodine uses one pillow and 3 minutes to develop
DPD method 8031, test 240


Anyone who had and can remember general lab practices has the basic skills to use this kit. Things like triple rinse with ro/di, meniscus, accurate measuring and attention to detail. One note of warning. The sample sizes for most of the tests is 25ml. A great thing as it decreases the error factor but it also mean more reagent. In many cases the reagent is toxic or highly reactive. Cadmium(nitrate) alone is not safe but when you add in nessler(ammonia), the strong acids and basic chemicals you need to be careful. All or most of the above test also have standards, so you can verify your results. I’m only a bit nuts, the cost for these standards is too much. Having many other test kits and a long enough testing phase I’ve compared results from each for long enough to be very secure with the Hach results.

So it has a large upfront cost, it is not quick to use, it’s big, it’s not in an attractive green or red package, nor does it have a cult following in the hobby. What it does do is combine all of the functionality of the other electronic testers and titration methods, removing their inaccuracy providing digital results for a price per test that is equal or better. If you compare the 3 common Hanna checkers initial cost, their reagent cost per test, marginal accuracy (the entire reason for testing) to the Hach kit plus the ability to test several other parameters… you make the decision.

So I open up the debate, questions, comments, pointing out I’m nuts, or just I’m wrong.

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#Part 2 - Temperature and Salinity
#http://www.chicagoreefs.com/forums/...-part-2-Temp-and-Salinity&p=242530#post242530
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I wasn't specific. The DR-2000 is several generations old and manufacture discontinued. It was new quite some time ago. The 1998 sales brochure for it has a user sitting in front of a PC w/o a CD rom drive, only a 2.5” floppy. Given that even analog spectrophotometers like the Spec-20 are still in lab use, the DR-2000 is far from obsolete.

LOL, I just found the PC requirements for the RS-232 software of the DR...

System requirements:
• IBM PC/AT or compatible with 386SX processor (16 MHz or better)
• 4 MB of RAM
• Hard disk drive with 2 MB or more of free space
• 3.5", 1.44 MB floppy disk drive
 
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jrpark22000 said:
Curious what you expected from a proper labratory spectrophotometer?
Click to expand...

Like i know what they cost or even r. Post said u picked up for 360$ so when i saw dicontinued and suggested replacement was 4 grand big jump from 360$ sorry dont know about spinkter meters.
 
It would be fantastic to have access to a full lab in this hobby. There is so much subjective BS with no objective testing thrown around in this hobby. It would be great to see real scientific analysis of people's tanks based on all the chemicals, additives, carbon sources, vitamins, etc. people toss into their tanks.
 
I share your thougths Ted. Sometimes tossing in stuff (ex. bayer dip) really advances the hobby, but too many times it doesn't. Short of a full lab, accuracy in testing can help cut the BS.
 
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While searching advancedaquarist I came across this related article. It’s a review of the smaller HACH colorimeters which are now out of production (replaced by DR900,) but still available on ebay. Prices in 2005 ranged $600-$1k but the article goes into what a colorimeter and spectrophotometer offer vs test kits. The DR800 series in the article covers uses the same reagents as the DR2000 I use.


http://www.advancedaquarist.com/2005/6/review

Many hobbyists rely on their animals' overall health as indicators of proper environmental conditions. We certainly can't argue of the successes achieved with this method - the method is simple and inexpensive. The main drawback of this technique becomes apparent when the ecosystem stumbles or fails. Without baseline datum for comparison, the reefkeeper is at a loss to explain what happened, and worse, how to prevent a reoccurrence.

It is much better to routinely monitor (and record) critical parameters within the aquarium. Generally, those 'test kits' marketed in the pet industry are colorimetric, that is, a chemical reagent is added to a known volume of water and, after a prescribed time, the resulting color is compared to a color chart, and an estimation of concentration is made. Results of testing involving 'test kits' can sometimes be notoriously difficult to interpret, and can be frustrating. Judgment of colorimetric test results is subject to many variables, such as intensity of color development, lighting conditions, color perception, etc. I suppose we've all at one time or another been guilty of drafting our Significant Other for an independent confirmation of what we perceive as a 'correct' determination. And, at the same time, we've secretly wished for a better way.

'Test kits' generally deliver 'ballpark' numbers, and this may be fine for the average hobbyist. However, serious hobbyists, coral farmers, professional aquarists and those providing aquarium maintenance services might be interested in some of the newer test equipment finding its way to market. Although not inexpensive, new colorimeters using light-emitting diodes (LEDs) have lower prices than units available just a few years ago. Sturdy and compact, these instruments are easy to transport for field work, yet are right at home in a laboratory setting.
Recent 'coral projects' required an upgrade to my older test equipment. My first inclination was the purchase of a 'bench' spectrophotometer. My previous experience with these instruments was the foundation of my initial decision, and, being a creature of habit, my familiarity - as well as the outlay - for this instrument seemed acceptable. I also investigated the purchase of a handheld, portable and battery powered colorimeter. After weighing the pros and cons, I decided to purchase a Hach DR/890 Colorimeter.

The Hach Company in Loveland, Colorado has for many years been a familiar name to those involved with water or wastewater treatment. In fact, their products have been marketed to the pet industry under private label for use in colorimetric determinations of various parameters. I have generally been satisfied with my experiences with Hach's products and felt comfortable with the purchase.

The colorimeter arrived in two days' time, and I anxiously unpacked the boxes. In it were the DR/890, sample vials, various adapters and an instruction manual. Test reagents, which have to be ordered separately and at additional cost, had arrived also. Except for installation of the AA batteries (included), the DR/890 is ready to use. It comes programmed with information to perform 90 tests via a simple menu (Note - The DR/820, 850 and 890 can be programmed by the user for up to 10 additional tests, with 12 data points for each). The instruction manual gives clear, easy to follow directions. The Hach colorimeters also have a built-in timer function that alerts the user when the proper reaction time has elapsed.

The DR/890 is a rugged unit, and Hach advertises the DR series colorimeters to be chemical resistant, shockproof, dustproof and waterproof (to the depth of 1 meter for 30 minutes - forgive me when I say I cannot verify this!). It can operate in temperatures of 0-49º C (32-120º F). Though rugged, the instrument should be treated with respect. Hach offers a carrying case at additional cost, but I found an aluminum case with interior foam padding at Lowe's for less than $30.

The DR/890 can perform 90 pre-programmed tests (the DR/850 can do 50, and the 820 is programmed with 20). See Table One for a partial list of tests. Test reagents are available in several forms (see photo). Perhaps the most familiar are dry reagents packaged in foil packets. The package is torn (or cut) open, and the contents added to a pre-measured water sample. The sample is then mixed with the chemical reagent(s) and a predetermined reaction period begins (conveniently timed by the colorimeter, which has appropriate times programmed for each test). A color develops, the instrument is zeroed with a 'blank' sample, the absorbance of the test sample is measured and -voila! - the instrument reports the result.

Hach offers reagents in packages other than the foil packets. The AccuVac ampul is a glass vial (~2.4 cm diameter) containing a measured amount of reagent packaged under a vacuum. When the AccuVac ampul is immersed in a sample and the tip is snapped off, a predetermined amount of sample of sample is sucked into the vial. After color development, the glass AccuVac, acting as a cuvette, is inserted into the colorimeter and the concentration is determined. A third method is the Test 'N Tube. Like the AccuVac, the Test 'N Tube contains reagent, and one simply adds the sample of interest and, after the prescribed reaction time, a determination is made. The Test 'N Tube vial diameter is ~1.5 cm and requires an adapter (Hach includes an adapter with each colorimeter).

While not inexpensive, the price of these colorimeters is much less than a full-blown spectrophotometer. This is due to the incorporation of light-emitting diode (LED) technology. Instead of full spectrum light being split by a prism or diffraction grating, an LED can deliver a light beam of relatively narrow spectrum. The DR/820 contains one LED (green at 520 nm); the DR/850 has 2, one each at 520 nm (green) and 610 nm (red); the DR/890 has four LEDs: 420 nm, 520 nm, 560 nm and 610 nm. So, the limitation of the instrument is not simply one of only programmed function, but one of wavelength range.

Data logging capability is possible. Results (up to 99) and date and time, test parameter, program number, concentration/absorbance/transmittance, sample number and instrument serial number are stored in an internal, non-volatile memory. This is a very convenient feature (as anyone who has tried to record to results with wet hands and wet paper can attest!).
Results can be expressed in various chemical species. For instance, ortho-phosphate can be reported as P, PO4, or P2O5. A simple press of the button alternates between these forms thus preventing use of a calculator.

Still, with all these features, the DR/800 series is not for everyone. However, cost (the major drawback) is a double-edged sword - For those used to 'test kit' prices, the cost will come as a shock; those familiar with pricing of 'laboratory grade' instrumentation will find the cost refreshing (especially when compared to a spectrophotometer). When one considers the cost of individual test kits (say, ammonia, nitrite, nitrate, pH, phosphorus, iron, etc.) we begin to understand that these colorimeters aren't really that expensive after all. If you need further justification, consider that these units can test tap water, RO effluent, spa and hot tubs, boiler water (!), swimming pools as well as aquaria.
Reagents are purchased separately at additional cost. Hach dates each reagent packet with an expiration date, so one is assured of reagent quality. Most parameter reagents are reasonably priced (especially nutrients such as ammonia, nitrate and phosphorus) at $20 - $30 for reagents sufficient for 100 tests. (Compare the cost per test with those reagents packaged for the aquaria industry in lots of 20 or so.) Some, such as potassium, are more expensive at about $1 per test (purchased in a package of 100). In some cases, one could already have the appropriate reagents. Hach's reagent packets are sometimes private-labeled for the pet industry and may be available in smaller quantities at your local pet shop. Some reagents can test for more than one parameter - The chlorine test reagent DPD can also be used in a user-entered iodine test (DR/890 only).

In rare instances, one does not necessarily have to use Hach reagents. It may be possible to purchase 'hobby' test kits (such as Salifert, Seachem and others) and manually calibrate the instrument for parameters such as strontium and iodide. This will require a knowledge of extinction coefficients, maximum absorption at proper wavelength and so on. Perhaps this is the true beauty of the Hach colorimeter series. It can satisfy the requirements of those with knowledge of chemistry and physics and let them manipulate the Beer-Lambert Law as they wish. Or, it is just the ticket for the advanced hobbyist/professional aquarist simply wanting an improvement over visually-judged results.
Postscript: I've tried to make this article as accurate as possible, however, errors can happen. It is also possible that Hach will change specifications from time to time. For further information, visit www.hach.com for the latest information.
 
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