How do you read your liquid test kit?

A

ariston

AC Members
Mar 22, 2005
54
0
0
Tucson, Arizona
There is a related thread going on, but I thought I'd start one on this question specifically. The way I've developed for reading my own test kits is to hold the test tube at an angle over my stove top (which happens to be bright white), under a bright white light. I adjust the height at which I hold the tube until there are no shadows or glare through the tube. I assume gives the "true" color of the liquid.

But the advice with the test kits seems to advise holding the tube right against (touching) the white part of the card, under a bright light. When I do this a lot of glare is produced -- it almost looks like the liquid is fluorescing. This doesn't seem right. And it can make a difference. On the AP nitrite test, for example, the difference between this method and the one mentioned above can be substantial -- up to 1.5 ppm difference in the reading.

What are other people's experiences/recommendations on reading liquid test kits?
 
I wish they would make electronic digital test cheaper, then nobody would have problems reading the colour card.And if you are colour blind like me, you have to get someone else to read the test for you.
 
I always take readings in my washroom under a white light. That way it's always the same lighting. I look quickly at the card too otherwise my eyes start playing tricks and the more I look, the harder it is to differentiate between the colors.
 
I usually end up wandering around the house, turning on lights, holding it up to various spots on the wall, I have the problem you do! I usually end up with some sort of glare and it looks like I'm not seeing the color quite right! :rolleyes:
 
i rarely use cards. If the importants (ammonia , nitrite) have a color change then something is bad. so if its not clear or blue something wrong. the more not clear or not blue it is the more you have to do to correct it.

nitrate. my test is unreadble above the third block which ironically is what ive determined is too much. so if its less red than cherry red its ok.

dkh, ph are so closely linked ive never seen a difference ( i know there is, just never happened in my tank) so i usuaaly only test one at a time. again a color change on ph is bad (ie not 7.0) .. i keep my tank at 4dkh with baking soda and limestone substrate

i never test gh because my water is so soft i rarely use soap and have to beat the foam down in my tank around surface disturbances.

of course im using that master test kit (ap brand?) big box $20 .. good deal actually, they should include it in those kits they keep pushing.
 
I definately agree with maaltan 100 million %. IF you are keeping a log, write both numbers, and if there is any color in the important things, change the H20. I don't use cards much either...I realized this when I lost one card and had to wing it. It is much less brain racking and stressful that way.
 
I use the cards for nitrate, Po4, and ph. My instructions and cards are stapled to the underside of my hood door, so when I swing it open, they are right in front of my face, with the room lighting right behind me. On the Ca kit and hardness kits, its fairly easy to see the changes. I never test for ammonia and nitrite unless cycling, or if I see a problem. Chlorine falls under the class of "if the color changes there is a problem" so when I test it I just look for color changes against a white piece of paper.
I really consider my test numbers more as a reference than an accurate statement. I estabilish norms and watch for changes. When I'm not running some experiment, I generally test very little.
Dave
 
Of liquid tests (or tests to which reagents, liquid or powder, are added to a water sample) I always found the easiest to read were those that had a transparent color comparator. The sample color is compared to a colored plastic strip with variations in the color of the plastic strip corresponding to different concentrations of the substance you're measuring. That way, all you have to do is hold the test kit up to a piece of white paper and compare the sample to the plastic strip. It's much easier than comparing a sample of water to a colored card. (see picture at http://www.novalek.com/korgd18.htm to get an idea)

Kordon (maker of Amquel) makes these types of tests, and they are really easy to read. I don't know if other tests use this system, but they might be worth a try if you have a hard time reading the cards.

HTH,
Jim
 
You must log in or register to reply here.
AquariaCentral.com
Top Bottom