Api tests reliable?
- Thread starter Reef.Blue
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mdb_talon
2500 Club Member
Never had any issues with reliability myself other than maybe ammonia which i cant remember the last time i cared about. Biggest issue i have with them is precision. I commonly use for calcium testing because it is reliable and more than enough precision for my needs. Nitrate test also works fine for me and i use in my fish only tanks(but in my reef tanks i want a more precise low end measurement than they provide(ie it is very hard to tell if nitrates are 0 or 1,2,3 for example). Never have an issue with the alk test either but again it not as precise as i would like.
If you already have api i would focus on a good phosphate and nitrate test. When alk reagent runs out i would buy a better kit for that as well.
If you already have api i would focus on a good phosphate and nitrate test. When alk reagent runs out i would buy a better kit for that as well.
Idech
2500 Club Member
I use API for cycling and PH. For me it’s precise enough and I’ve been using them for a long them and never had any problems.
For Nitrates and phosphates I use Hanna. For magnesium, calcium and alkalinity I use Red Sea.
For Nitrates and phosphates I use Hanna. For magnesium, calcium and alkalinity I use Red Sea.
muzikalmatt
Valuable Member
Same here. For cycling, I find API to be accurate enough although sometimes you'll get false positives on ammonia. The main thing I want to see from the test when cycling is the presence of ammonia, nitrites and nitrates, not necessarily their precise levels.
I would add to the list @Idech provided that I highly recommend the Hanna alkalinity checker as well. It's probably their best checker overall as you can complete the test in roughly 60 seconds.
GARRIGA
2500 Club Member
Been using API since the 80s. Don't recall anything else available at the time. Have not validated against known sources but I'm more concerned with holistic changes than exact measurements. I am using Auto Aqua Magnetic Stirrer plus 20ml vials that are 27mm wide and fit perfectly in the stirrer which I believe helps with accuracy and ease of use. If needed, I have NeoNitro and NeoPhos which can be used to create a reference sample to test against but I mostly observe my tank. Can see based on algae growth/retrace whether certain nutrients are higher than expected. Test results correlate what I'm observing.
My one issue is KH. Had an overdose of TDO that was processed quickly through my nitrification resulting in no ammonia or nitrite spike yet nitrates through the roof. As expected, my KH should have dropped since nitrification does strip alkalinity and until my nitrates are process through denitrification than alkalinity won't be added back. Using Tropic Marin KH I'm getting a reading of 7 dkh yet API reading 9 dkh. Normally both are off by 1 dkh with API being higher. This is the first time API KH was so off and I'll be testing in a few days once carbon dosing reduces nitrates to acceptable levels below 20 ppm and preferably under 5 ppm that I tend to run. KH should be back to 9 dkh or higher.
I often wonder if the web just parrots what is read vs actually confirming what is read. Could also be reef shops rather sell the higher margin kits. Don't see any selling UF and those do work. More profitable to sell a ton of product vs letting nature do it's thing.
Final point. Consider following the instructions. Add a magnetic stirrer and at a minimum than API can be one's general use to keep an eye on parameters than if needed grab a Hanna checker and verify the results. When in doubt, create a sample reference and test the testers. I'm assuming the less one uses the Hanna checker than the longer it goes between calibrations. At least that's going to be my justification for this approach.
BTW, there's a distinct difference between accurate and precision. API can be accurate while Hanna is precision. Each has to decide which they need and often both can serve a purpose. Especially with Hanna Nitrate regent possibly being scarce. Which brings up another point. If API is so inaccurate than why did Reef Builders suggest using API Nitrate regent with a Hanna checker? They concluded it was relatively accurate. Wondering what other API regents can be used with the various Hanna checkers or this was a one off.
My one issue is KH. Had an overdose of TDO that was processed quickly through my nitrification resulting in no ammonia or nitrite spike yet nitrates through the roof. As expected, my KH should have dropped since nitrification does strip alkalinity and until my nitrates are process through denitrification than alkalinity won't be added back. Using Tropic Marin KH I'm getting a reading of 7 dkh yet API reading 9 dkh. Normally both are off by 1 dkh with API being higher. This is the first time API KH was so off and I'll be testing in a few days once carbon dosing reduces nitrates to acceptable levels below 20 ppm and preferably under 5 ppm that I tend to run. KH should be back to 9 dkh or higher.
I often wonder if the web just parrots what is read vs actually confirming what is read. Could also be reef shops rather sell the higher margin kits. Don't see any selling UF and those do work. More profitable to sell a ton of product vs letting nature do it's thing.
Final point. Consider following the instructions. Add a magnetic stirrer and at a minimum than API can be one's general use to keep an eye on parameters than if needed grab a Hanna checker and verify the results. When in doubt, create a sample reference and test the testers. I'm assuming the less one uses the Hanna checker than the longer it goes between calibrations. At least that's going to be my justification for this approach.
BTW, there's a distinct difference between accurate and precision. API can be accurate while Hanna is precision. Each has to decide which they need and often both can serve a purpose. Especially with Hanna Nitrate regent possibly being scarce. Which brings up another point. If API is so inaccurate than why did Reef Builders suggest using API Nitrate regent with a Hanna checker? They concluded it was relatively accurate. Wondering what other API regents can be used with the various Hanna checkers or this was a one off.
Last edited:
DannoOMG
Active Member
API was once described to me as a "good indicator of a problem."
Like if your Nitrates are completely out of whack in the 40ppm zone or other parameters it will tell you. But as far as accuracy goes. Bleh.
Like if your Nitrates are completely out of whack in the 40ppm zone or other parameters it will tell you. But as far as accuracy goes. Bleh.
IME, the only API test I would use is the ammonia one to get info on cycling. Salifert is good for Ca, Mg, and their ALK test is pretty easy to use. I recently ran into a big issue with Salifert NO3 - it was showing 25+ when the actual value was less than 4 - and I had been dumb about it - I usually test my test kits with a standard, and didn't when I replaced my previous NO3 Salifert kit. Lost a few corals and started back down the algae path as I had essentially allowed NO3 to bottom out. Maybe Elos would be a better option for NO3 - I know their PO4 kit that I have is very good - have tested against a standard. I have since moved to HACH for NO3 - not cheap, but lab grade and the color disc is super easy to read.
JachPot
Active Member
I bought the API kit to check Ammonia, Nitrite, Nitrate for the cycle. Just $20 to watch the cycle take place and know where you're at.
Past that I'm going to finish out the nitrate bottle and move on. I've already bought Salifert Calcium, Mg, and KH tests. I'll grab a Nitrate test soon and eventually a Hanna phosphate kit.
Past that I'm going to finish out the nitrate bottle and move on. I've already bought Salifert Calcium, Mg, and KH tests. I'll grab a Nitrate test soon and eventually a Hanna phosphate kit.
Azedenkae
Valuable Member
What @Spare time said. They are reliable. I don't think a lot of people here can differentiate between 'reliable' and 'accurate'. Or 'precise', rather.
Their resolution is not great at higher concentrations, not that it matters that much. They can also throw false 0.25ppm ammonia readings, but this happens with other test kits too (not necessarily 0.25ppm per se, whatever is the first value above 0 for other kits).
Their nitrate kit is affected by the presence of nitrite, but again so are other kits.
They can give different readings compared to other test kits, but again this applies to other test kits.
On the other hand, yes they would throw up the same numbers each time. You may have some issues with old bottles, but again this applies with any other test kit.
So... yeah.
I tried other kits, decided to go back to API because I have no real issues I would not have with other kits.
Of course, there are also some really accurate tests out there. So compared to them, yes API and a lot of other test kits are terrible lol.
Their resolution is not great at higher concentrations, not that it matters that much. They can also throw false 0.25ppm ammonia readings, but this happens with other test kits too (not necessarily 0.25ppm per se, whatever is the first value above 0 for other kits).
Their nitrate kit is affected by the presence of nitrite, but again so are other kits.
They can give different readings compared to other test kits, but again this applies to other test kits.
On the other hand, yes they would throw up the same numbers each time. You may have some issues with old bottles, but again this applies with any other test kit.
So... yeah.
I tried other kits, decided to go back to API because I have no real issues I would not have with other kits.
Of course, there are also some really accurate tests out there. So compared to them, yes API and a lot of other test kits are terrible lol.
Squidmotron
Community Member
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Someone actually did a fairly scientific study of this some years back.
Yes, they are as reliable as any test. They just aren't as fine-grained. It depends on how precise a reading you need.
Yes, they are as reliable as any test. They just aren't as fine-grained. It depends on how precise a reading you need.
