Lighting when viewing test kit results? - 6/12/07
First, thank you for being such a valuable resource for the hobby!
<You are welcome on behalf of the crew.>
My question falls with how should you view your test kit results, specifically in what type of lighting? I am using a liquid test kit, and I have noticed that my results can be read differently under different lighting do to the color spectrum the lights produce. For example: under tungsten light my pH reads off the chart on the high end (over 8.6), next to my window it matches the pH 8.0 level, and next to my aquarium (one actinic and one 10,000K bulb) the reading is more at pH 8.2. With such varying results I am unsure where to read my results. Can we (as hobbyists) assume that the manufactures assumed that we will be testing under normal tungsten light-bulbs and designed the test accordingly? Or since there is so much variance between all testing supplies is there no real standard viewing requirement, and if so, how do I know which result to read?
<Since there is so much variation in color of bulbs, even common incandescent ones, I tend to trust the natural light the most. And I get the most consistent results from different manufacturer’s kits if the results are all read in natural light. I find the indirect light by a big window or in the shade on the porch works best. More to read here:
http://www.wetwebmedia.com/mtestliq.htm >
Thanks for your input in this matter.
Esther See
<Welcome, Alex>

Copper, other colorimetric assays – 04/30/07
Gentlemen (RF in particular)
<Yes>
Thank you for your help and advice on Copper and test kits.  It's become something of a quest / mild obsession with me to explain why the manufacturers can't see what WE all see - namely that squinting into vials next to paper cards almost always yields the universal result "Gee, it's KINDA like THAT color, but the hue is completely different and maybe if I discount THAT ... then maybe it looks more like THIS color...."
I'm wondering if actual photographs of the identical vial with real-world colors wouldn't be better.
<Mmm... actually... a plug here for colorimeters, spectrophotometers... and calibration (of course) of the same... Machines that can/do measure transmittance, and its reciprocal (absorption) accurately...>
I'm wondering if chemists have the ability to make the color differentiation between, say 2.0 and 2.5 much greater than they currently are.
<For some types of tests... yes... mostly this is a matter of net cost...>
I'm wondering if some chemist COULD make the colors "night & day" different & foolproof  *IF* we didn't mind paying $50 per kit
<Bingo!>
Has anyone every tried improving the test readings like this on their own?
<Likely so... please see Hach, LaMotte's websites... re this gear and the tools mentioned above>
Regards
Abell
<Thank you, BobF>

Water Test Methodologies/Varying Qualities in Equipment - 05/30/06
Hello!
<<Howdy!>>
I have run up against a problem that is frustrating me to no end-
I'm hoping you can help.
<<Mmm, okay...let's see what I can do>>
Every gadget or test kit I seem to purchase gives me a different reading on tank specs.
<<Not atypical>>
For example:
Digital thermometer- 74 degrees in tank.
Floating analog (red-dye style) thermometer - 79 degrees in tank.
Refractometer - 1.025 spg.
Hydrometer - 1.020 spg.
Mardel dip strip test for Nitrate - 40 ppm
Hagen reagent test for Nitrate - 10 ppm
Similar situation with some other tests kits as well.  Who do I believe?
<<Okay Stephanie, you're comparing apples to oranges...the differences you are seeing come from the differences in "quality/reliability" among the differing instruments/test kits you are using.  The floating thermometer is useful for detecting changes in temperature, but the inexpensive hobby grade models are usually anything but accurate. The same can be said of the hydrometer (both glass and plastic).  Accurate glass hydrometers can be had, but for the hassle involved with using one correctly, if you're going to put out 40-60 bucks for a hydrometer you may as well add a bit more money and get a good refractometer...or my personal choice, a salinity meter.  As for the nitrate test, the dip strips are useless in my opinion, I'm not surprised at the difference in the readings.  Stick with a quality reagent test kit (Hagen is "ok", but you may wish to look in to Hach, LaMotte, Salifert, or Seachem for better quality test kits).  Stick with the digital thermometer, the refractometer, and even the Hagen test kits (make sure they are new/fresh) and you'll be fine>>
I am doing the tests within the same 5-minute interval.  Right now I'm choosing to believe whichever test I like the results of the best.  I'd like to take a more scientific approach to it....
<<Not all "black and white" here...much to be learned and "felt" in this hobby.  Even those "hobby grade" instruments and cheaper test kits (NOT the test strips!) can be used successfully as long as you recognize their limitations/quantify the results against a benchmark.  You already have access to the tools...the knowledge/understanding will come...>>
Thanks!
Stephanie D.
<<Is a pleasure to assist.  EricR>>

Ammonia Source for Experiment
Dear Crew:
As part of a school science fair project about aquariums, my 9 y/o daughter is going to be testing the sensitivity and reliability of Seachem's Ammonia Alert. What would be the best inexpensive, easily obtainable source of quantifiable ammonia to add to the water she'll be testing this product in? Of course, no fish are involved in the test--she'll be using glass containers of just saltwater (1.025) and just fresh water. Thanks, Steve Allen.
<I would use simple "cleaning ammonia". that can be serially diluted (it still is a breathing irritant, so please do the dilutions for your daughter), making "stock" solution of a known concentration (look into a Hach or LaMotte... or even a Salifert test kit for ammonia to "check the checker" (the Ammonia Alert tm).
Bob Fenner>

Where can I get buffers for calibration?
I've received an electronic pH tester, but it didn't come with calibration buffer...
I need a buffer with pH or 7.01 and then either 4.01 or 10.01 to calibrate it.
Where can I buy this (or what can I use?)
thank you,
Luke
<Mmm, I would buy such "standards"... either from/through the industry (try Marine Depot or Custom Aquatic... links on WWM, or through a chemical supply biz on-line. Use your search engine and the term "pH standard solutions". Bob Fenner>

Test Kits?
Robert,
What do you think is the best all purpose test kit for fresh and salt water tanks? Hagen Aquarium Master kit?
<LaMotte, Hach, YSI... other folks make "fisheries", "water quality" kits that include spectrophotometric, titrametric as well as more-accurate-than-one-needs colorimetric (like most pet-fish units) assays with a whole bunch of testing parameters... but the Salifert and Tetra kits are likely about the best for aquarist use. Please read over the FAQs posted on our site: www.WetWebMedia.com re tests/testing. Bob Fenner>
Thank You Tanya Hawkins

Nitrates quickie question
Hi Guys
<Cheers, dear>
Just a quickie - we cannot get an accurate reading for nitrates in our marine tank. Currently we use three - a tab test, powder and liquid. The results are:
Tab test - 100ppm +
Powder - 50ppm
Liquid - 10ppm!
Quite a difference! All tests are relatively new. Which would you rely on?
<well as a rule, dry reagents are more reliable and longer lived (shelf life) than liquids. Have you checked the dates of all reagents to be sure that they are fresh? Also know that test kits may read nitrate as an ion or as nitrate-nitrogen and there is a difference of 4.4 with the multiple. So.. a reading of 10ppm with a multiple factored in could very well agree with the 50ppm reading (one in the same). Do read your test kits more closely to determine what form of nitrate they are actually reading and if the reagents are actually not expired>
Thanks Lesley
<kindly, Anthony>