Learning to Use API Tests -- I'm an Idiot!!!

[brian1973]

Originally Posted by Kissyboots

I'm sure some have seen my thread about me not having nitrates and then all of a sudden I do.

Summary: The test strips I used to use always gave me around 20ppm. Then I started the API and it always told me 0ppm. At the last wc, API tells me 5ppm on the 20g but not on the other two tanks. I am testing correctly, just like it says on the card. Did I miss something??

Not sure if your missing something kissy but I was using test strips when I started then after joining this forum I took the advice of others and bought the API kit. I did compare my test strips to the API and my reading where always the same, so I use the test strips as a regular test and use the API kit about monthly now, I also use the strips at the same time to compare reading as well.

When you do the nitrate test properly you will see the color change almost immediately, mine actually is ready for reading in about 2 mins. but I wait the full 5 mins to be safe.

[iapetus]

Originally Posted by Kissyboots

Let's see...I don't have strips anymore but I kept the box (I keep everything...) It goes from 0-20-40-80-160-200

OK. That's kinda what I was getting at with my questions. I'm hypothesizing that your strips were measuring some nitrates. Unfortunately, the gradation on those strips aren't all that fine. Any measurable amount would show up as 20 ppm, I'm guessing. So, even though you weren't that high, you had some and it came up as 20 ppm.

I find that matching the colors on the API charts is rather imprecise, particularly if the readings aren't close to zero. It could be that the API tests were giving you something above zero, but not quite discernible from zero. Maybe a little extra pushed you to the 5 ppm mark. So, you've had some nitrates all along, but the tests have been difficult to interpret for such low levels.

It's important that we think about the limits of our testing equipment when we use it. The way these aquarium tests work don't provide error bars and they have limitations. A color that I think closely matches 0 ppm of ammonia might be interpreted by someone else to read 0.25 ppm of ammonia. So, the subjectiveness of these API tests is another weakness of them. They're good guides, but they're imprecise.

[Kissyboots]

Weird. My nitrate never changes from yellow, except last time of course.I guess I'll recheck my way of testing next time.

[Whiskers]

Originally Posted by iapetus

It's important that we think about the limits of our testing equipment when we use it. The way these aquarium tests work don't provide error bars and they have limitations. A color that I think closely matches 0 ppm of ammonia might be interpreted by someone else to read 0.25 ppm of ammonia. So, the subjectiveness of these API tests is another weakness of them. They're good guides, but they're imprecise.

I have to agree with you iapetus in that these tests, whether they are dip strips or chem tests with drops, are just basic guide lines. I've use them both and sometimes the wife and I can slightly dissagree about the color results. We figure as long as we are really close and every thing is well within its specs then we are ok.

[Avalon]

Avalon's guide to API test kits (for fish):

Ammonia & Nitrite: If it changes color, you have too much.
Nitrate: If it is yellow or light orange, you're good. If it's dark orange or reddish-orange (and any further degree of red), you have too much.
GH: Throw it in the trash.
KH: If it changes color, the drop it changed color on is the degree of KH.
PH: Dark blue is around 7.8-8.0+, medium to light blue is 7.2-7.8, light greenish is about 6.8-7.2, yellow is battery acid (I kid, but it's pretty low)

[emmanuelchavez]

OK. Retested the way the instructions say to... I still have only 5 ppm Nitrates. I would've thought the nitrates would be high in the 10 gallon, since I took out the live plants and it's overstocked with all those guppies.


Probably shouldn't count my blessings too soon, I'm sure that if I retest in a couple of days, they'll go up...

[Stykman]

Not for anything, but I just tested my 55 Gal in my son's room...with.....Drum Roll Please....The new API Master Test Kit I just got the other day.

pH Fine.
Ammo - 0
Nitrite - .25 ppm...ok...we'll deal.
Nitrate - Followed the Instructions to a T. I didn't make the common mistake of not shaking the Bottle #2 before actually adding it to the test tube. Shook the tube 1 Minute, set it down, waited 5 mins, picked it up, grabbed the card, and.....

Uhh...Ummm...Let's try over here where there's more light...no...how about the bathroom...yea, MUCH more light in here...Humph...

I have 20/20 vision. I can read a car license plate from about 50 feet away. I can see all the colors you can possibly dream of. Meaning, My eyes are fine.

Can anyone tell the difference between 40 / 80 on that Card? There is the SLIGHTEST difference between the 2, I can see that...but to compare them to the tube? Forget it.

I'm changing the water anyway, but I used to do changes at 60 ppm...now I guess if it's 40...it might as well be 80, so where's that siphon hose???

[iapetus]

Originally Posted by Stykman

Can anyone tell the difference between 40 / 80 on that Card? There is the SLIGHTEST difference between the 2, I can see that...but to compare them to the tube? Forget it.

Nope, I can't tell the difference for all the world. That's why I think like Avalon does about this. I'm not so concerned about the exact number, especially seeing as how fish can tolerate some level of nitrates. I just want to see orange or yellow from the nitrate test ... which is why I've had to keep doing water changes on my recently cycled 29G.