how inaccurate is API testing kit?

mjaquarium02 · Jun 7, 2023

hey saltwater fish gang,

i was just wondering how inaccurate is the API testing kit? i have a fish tank that i’ve been testing with API but I’ve read from past experiences that Ammonia is usually super inaccurate, but what about the rest? PH, Nitrite, and Nitrate? are those a bit better? I found a LFS that tests water with Red Sea and Hanna test kits. Is that better?
What testing kit do you guys recommend?

thanks!

saltyfins · Jun 7, 2023

reefaholic2023 said:
hey saltwater fish gang,

i was just wondering how inaccurate is the API testing kit? i have a fish tank that i’ve been testing with API but I’ve read from past experiences that Ammonia is usually super inaccurate, but what about the rest? PH, Nitrite, and Nitrate? are those a bit better? I found a LFS that tests water with Red Sea and Hanna test kits. Is that better?
What testing kit do you guys recommend?

thanks!

it's really not at all accurate. Red Sea, Nyos, Hanna... go that route. You'll be a lot safer and happier

Goaway · Jun 7, 2023

Ammonia is off from. .25 to .5

Nitrate, alk, calcium seems to be reliable as redsea test kits.

I know, because i use redsea for calc, alk, mag and also have salifert alk test. The lfs only uses api. But, that's all i can compare too. The alk test on all 3 read the same.

jabberwock · Jun 7, 2023

saltyfins said:
it's really not at all accurate. Red Sea, Nyos, Hanna... go that route. You'll be a lot safer and happier

Hogwash. They are clinically accurate. The problems lie in the person performing the tests, and the subjective interpretation of colors. You can spend more and make your life easier for sure, but if you do it right, API will suffice.

Mr. Mojo Rising · Jun 7, 2023

I think they are sufficient indicators to get you through a cycle, no need for that kit once the cycle is done. But to answer the question, yes, I would trust the API nitrate tester. (no need to ever test nitrite)

Personally I think only a low nutrient tank would require something super precise, but I don't have a problem with low nutrients. To be honest, I haven't done a nitrate test in over 2 years.

Outlaw Corals · Jun 7, 2023

I like API over the hanna and Red Sea

thatmanMIKEson · Jun 7, 2023

API get less accurate, with more IPA..

Goaway · Jun 7, 2023

I think api gets a lot of flack because the test vials are not cleaned/dried properly.

I used a dosing cup to get tank water from and to test the big 3. The readings were so out of the roof... I just grabbed a glass, got new water and re-ran my tests. Left over residue will mess with your tests.

PotatoPig · Jun 7, 2023

Goaway said:
Left over residue will mess with your tests.

First time I tried my Hanna copper checker the results were off the chart. For a minute I thought I’d massively messed up the dosing until I realized I’d used the same 10ml syringe to get the sample as I’d used to dose the tank with copper…

Reef_Tank_Fan_SC · Jun 7, 2023

No test kit is dead accurate unless you go with the lab grade kits that are expensive. All hobby grade kits are usable and I think they are a matter of user preference honestly. I have a uncle that’s had a red tank in his house for the last 20 years and he has never used anything but API. I’m colorblind so I use Hannah because I get better water that way, but I’ve had people tell me they aren’t that good either. Best case is to find a kit you like and then dbl check your results with another kit or at a lfs

EeyoreIsMySpiritAnimal · Jun 7, 2023

API is not inaccurate, their tests are just less precise and the ammonia measures total ammonia, not just free (harmful) ammonia. Used correctly, and understanding that one nuance, API tests are absolutely fine, especially for cycling a tank.

(If I didn't practically throw my shoulder out shaking the nitrate reagents, I'd consider using API long term! Lol)

seanarino · Jun 7, 2023

From a freshwater standpoint - API isn't actually *inaccurate*, it's just that the colors are really hard to discern - Hanna checkers basically do it for you rather than having to go "mmm, I dunno, that looks a little purple, a little blue...."

KrisReef · Jun 7, 2023

seanarino said:
From a freshwater standpoint - API isn't actually *inaccurate*, it's just that the colors are really hard to discern - Hanna checkers basically do it for you rather than having to go "mmm, I dunno, that looks a little purple, a little blue...."

Yup, I got those expensive Hanna's because my wife wasn't always around to rekon the spectrum from beyond and tell me what the mysterous vial was indicating regarding the hidden otherworldly spirit activies revealed in shades of blue that I were supposed to compare with the purple/violet shades indicated on the comparator paper that came with those test kits.

Propane · Jun 7, 2023

Lol I feel ya @KrisReef. Been using an aquaforest for my alk. I just let her tell me when it turns pink.

seanarino · Jun 7, 2023

KrisReef said:
Yup, I got those expensive Hanna's because my wife wasn't always around to rekon the spectrum from beyond and tell me what the mysterous vial was indicating regarding the hidden otherworldly spirit activies revealed in shades of blue that I were supposed to compare with the purple/violet shades indicated on the comparator paper that came with those test kits.

Also, the fact that for freshwater specifically, API is more-or-less the "be all, end all" (despite there being Hanna checkers for freshwater...) and it's like, uh, what about colorblind people.... Hanna checkers tell you numbers! They don't make you look at colors! They do that!

ptrusk · Jun 7, 2023

One thing about the API tests is the level marker on the vials. As I recall for HS chem, you use the bottom of the maniscus as your reference. But that line varies from vial to vial. In a pinch, I once used their calcium test, but with a 5ml syringe and the results were repeatable. Were the numbers correct, who knows but really that is the same as any test kit. For beginners seeking stability I say they are fine as long as you perform the test the same way every time. It is a cheap way to get the hang of testing.

Personally, I use hanna for colormetric tests (nitrate, phos) because no matter what kit I can't discern the proper color. Titration is easy for me. And really, if you are growing softies, does it really matter that much?

seanarino · Jun 7, 2023

ptrusk said:
One thing about the API tests is the level marker on the vials. As I recall for HS chem, you use the bottom of the maniscus as your reference. But that line varies from vial to vial. In a pinch, I once used their calcium test, but with a 5ml syringe and the results were repeatable. Were the numbers correct, who knows but really that is the same as any test kit. For beginners seeking stability I say they are fine as long as you perform the test the same way every time. It is a cheap way to get the hang of testing.

Personally, I use hanna for colormetric tests (nitrate, phos) because no matter what kit I can't discern the proper color. Titration is easy for me. And really, if you are growing softies, does it really matter that much?

I like having an API test kit on hand for certain things, but boy I wish I struck it rich so I could buy all the colorimeters and a big ol' bag of reagents and never have to worry again!

Frankly, because I don't have a saltwater API test kit, (I do have actual test kits) I usually just use 9-in-1 strips for when I'm doing "non important" testing so I don't have to buy so many reagents again

The stuff that's actually important I use the real test kits for, but the stuff that isn't life or death just gets the strips.

ptrusk · Jun 7, 2023

seanarino said:
I like having an API test kit on hand for certain things, but boy I wish I struck it rich so I could buy all the colorimeters and a big ol' bag of reagents and never have to worry again!

Frankly, because I don't have a saltwater API test kit, (I do have actual test kits) I usually just use 9-in-1 strips for when I'm doing "non important" testing so I don't have to buy so many reagents again

The stuff that's actually important I use the real test kits for, but the stuff that isn't life or death just gets the strips.

Full disclosure, I have been doing this for 20 some years