Anybody using API test kits?
- Thread starter Mr. Ugly
- Start date
finalphaze987
Supporting Member
I use the alk and Ca...i round down with all my readings (1-2 dKh, and 20-40ppm for Ca)after i compared them to a buddys salifert..
Mr. Ugly
Past President
Ok, just got done playing around with 3 API alk kits and the last of my Salifert.
I ran the Salifert in high resolution mode and came up with 2.86 meq/L for one sample. That works out to 8dKH.
Running the API kits according to the directions multiple times gives me 10dKH for the same sample.
I decided to rerun the titrations using the API reagent, but out of a Salifert syringe for more precise measurement. An API drop is about .039 ml vs. a Salifert drop at .019 ml. (I measured the volume of a bunch of drops of each and divided by the number of drops.)
Going to the bright yellow endpoint, which still actually had a hint of green, I used .36 ml of reagent. This worked out to about 9.25 dKH. The API kit reads at least 1.25 dKH higher than the Salifert for that alk level.
I reran the API/Salifert reagent/syringe combo a few times and found that API and Salifert kits agree if I go by the first hint of API color change and subtract .02 ml. from the total volume used.
I'll run another batch of tests on some fresh RC, but for now I'll be using API reagents out of the Salifert syringe and tip.
I made up a chart for Salifert(low res) and API using volume of reagent and meq/L alk.
ml. Salifert API
reagent (meq/L) (meq/L)
0.01 0.11 0.09
0.02 0.23 0.18
0.03 0.34 0.27
0.04 0.46 0.37
0.05 0.57 0.46
0.06 0.69 0.55
0.07 0.80 0.64
0.08 0.91 0.73
0.09 1.03 0.82
0.10 1.14 0.92
0.11 1.26 1.01
0.12 1.37 1.10
0.13 1.48 1.19
0.14 1.60 1.28
0.15 1.71 1.37
0.16 1.83 1.47
0.17 1.94 1.56
0.18 2.06 1.65
0.19 2.17 1.74
0.20 2.28 1.83
0.21 2.40 1.92
0.22 2.51 2.01
0.23 2.63 2.11
0.24 2.74 2.20
0.25 2.86 2.29
0.26 2.97 2.38
0.27 3.08 2.47
0.28 3.20 2.56
0.29 3.31 2.66
0.30 3.43 2.75
0.31 3.54 2.84
0.32 3.65 2.93
0.33 3.77 3.02
0.34 3.88 3.11
0.35 4.00 3.21
0.36 4.11 3.30
0.37 4.23 3.39
0.38 4.34 3.48
0.39 4.45 3.57
0.40 4.57 3.66
0.41 4.68 3.75
0.42 4.80 3.85
0.43 4.91 3.94
0.44 5.02 4.03
0.45 5.14 4.12
0.46 5.25 4.21
0.47 5.37 4.30
0.48 5.48 4.40
0.49 5.60 4.49
0.50 5.71 4.58
I ran the Salifert in high resolution mode and came up with 2.86 meq/L for one sample. That works out to 8dKH.
Running the API kits according to the directions multiple times gives me 10dKH for the same sample.
I decided to rerun the titrations using the API reagent, but out of a Salifert syringe for more precise measurement. An API drop is about .039 ml vs. a Salifert drop at .019 ml. (I measured the volume of a bunch of drops of each and divided by the number of drops.)
Going to the bright yellow endpoint, which still actually had a hint of green, I used .36 ml of reagent. This worked out to about 9.25 dKH. The API kit reads at least 1.25 dKH higher than the Salifert for that alk level.
I reran the API/Salifert reagent/syringe combo a few times and found that API and Salifert kits agree if I go by the first hint of API color change and subtract .02 ml. from the total volume used.
I'll run another batch of tests on some fresh RC, but for now I'll be using API reagents out of the Salifert syringe and tip.
I made up a chart for Salifert(low res) and API using volume of reagent and meq/L alk.
ml. Salifert API
reagent (meq/L) (meq/L)
0.01 0.11 0.09
0.02 0.23 0.18
0.03 0.34 0.27
0.04 0.46 0.37
0.05 0.57 0.46
0.06 0.69 0.55
0.07 0.80 0.64
0.08 0.91 0.73
0.09 1.03 0.82
0.10 1.14 0.92
0.11 1.26 1.01
0.12 1.37 1.10
0.13 1.48 1.19
0.14 1.60 1.28
0.15 1.71 1.37
0.16 1.83 1.47
0.17 1.94 1.56
0.18 2.06 1.65
0.19 2.17 1.74
0.20 2.28 1.83
0.21 2.40 1.92
0.22 2.51 2.01
0.23 2.63 2.11
0.24 2.74 2.20
0.25 2.86 2.29
0.26 2.97 2.38
0.27 3.08 2.47
0.28 3.20 2.56
0.29 3.31 2.66
0.30 3.43 2.75
0.31 3.54 2.84
0.32 3.65 2.93
0.33 3.77 3.02
0.34 3.88 3.11
0.35 4.00 3.21
0.36 4.11 3.30
0.37 4.23 3.39
0.38 4.34 3.48
0.39 4.45 3.57
0.40 4.57 3.66
0.41 4.68 3.75
0.42 4.80 3.85
0.43 4.91 3.94
0.44 5.02 4.03
0.45 5.14 4.12
0.46 5.25 4.21
0.47 5.37 4.30
0.48 5.48 4.40
0.49 5.60 4.49
0.50 5.71 4.58
finalphaze987
Supporting Member
[quote author=cwolfus link=topic=3011.msg34261#msg34261 date=1203399916]
[quote author=tuberider link=topic=3011.msg32497#msg32497 date=1202835662]
I use em cause their fast.
[/quote]
Hey Jeremy/Norman,
I haven't used them before. What makes them fast?
C
[/quote]
fill to the line, 1 drop of reagent at a time till you see a color change. and your done..
Interesting stuff Norm...thanks for running the test..it helps me justify the $8 i save buying API than others..it preformed alot better than i expected according to your observations.
[quote author=tuberider link=topic=3011.msg32497#msg32497 date=1202835662]
I use em cause their fast.
[/quote]
Hey Jeremy/Norman,
I haven't used them before. What makes them fast?
C
[/quote]
fill to the line, 1 drop of reagent at a time till you see a color change. and your done..
Interesting stuff Norm...thanks for running the test..it helps me justify the $8 i save buying API than others..it preformed alot better than i expected according to your observations.
Mr. Ugly
Past President
[quote author=cwolfus link=topic=3011.msg34261#msg34261 date=1203399916]
[quote author=tuberider link=topic=3011.msg32497#msg32497 date=1202835662]
I use em cause their fast.
[/quote]
Hey Jeremy/Norman,
I haven't used them before. What makes them fast?
C
[/quote]
Hehe... I'm faster with Salifert alk than with API
Salifert has the extra step of adding 1 drop of indicator solution before the titration, but that's no biggie.
People that like Elos probably will like API. Same count the drop testing method. Ok for trending parameters, but no good for fine tuning your kalk/2part/Ca reactor.
The Salifert syringe gives really good control, so I can work fast without having to worry about extra drops coming out like with the API bottle. Also, the Salifert vial is large so that it's fast to mix and titrate at the same time. I'll bring test kits to demo at the next meeting if you like.
If you use the API kit the way it was designed, you have to cap and uncap the skinny vial as you add drops and mix... messy and slow. You could do the finger flick method, but the vial is small enough that you don't get good mixing when you're close to the endpoint.
I actually don't like API or Elos, in case people couldn't tell by now
I'm just using API because Salifert is hard to find right now. And I found a way to make the API kit usable for me.
I use the API reagent with the Salifert syringe and tip. I don't use the dropper bottle. I use the large vial from the Salifert kit so I can mix while titrating. I stop titrating at the first hint of green, not yellow. And I take my endpoint to be .02ml(1 Salifert drop) less.
I use SeaChem for Ca and lately for Mg. I prefer Salifert Mg, but same problem with availability.
People on the RC Chem forum talk crap on the SeaChem, saying that it reads low for Ca. I'm able to get the same readings with SeaChem Ca as others get with Salifert Ca. The thing to remember is to go to the bright blue endpoint with SeaChem.
I like the Salifert tips. I use them with my SeaChem kits. A drop out of a Salifert tip is ~.02 ml. You can do half drops at ~.01 ml pretty easily.
[quote author=tuberider link=topic=3011.msg32497#msg32497 date=1202835662]
I use em cause their fast.
[/quote]
Hey Jeremy/Norman,
I haven't used them before. What makes them fast?
C
[/quote]
Hehe... I'm faster with Salifert alk than with API
Salifert has the extra step of adding 1 drop of indicator solution before the titration, but that's no biggie.
People that like Elos probably will like API. Same count the drop testing method. Ok for trending parameters, but no good for fine tuning your kalk/2part/Ca reactor.
The Salifert syringe gives really good control, so I can work fast without having to worry about extra drops coming out like with the API bottle. Also, the Salifert vial is large so that it's fast to mix and titrate at the same time. I'll bring test kits to demo at the next meeting if you like.
If you use the API kit the way it was designed, you have to cap and uncap the skinny vial as you add drops and mix... messy and slow. You could do the finger flick method, but the vial is small enough that you don't get good mixing when you're close to the endpoint.
I actually don't like API or Elos, in case people couldn't tell by now
I'm just using API because Salifert is hard to find right now. And I found a way to make the API kit usable for me.
I use the API reagent with the Salifert syringe and tip. I don't use the dropper bottle. I use the large vial from the Salifert kit so I can mix while titrating. I stop titrating at the first hint of green, not yellow. And I take my endpoint to be .02ml(1 Salifert drop) less.
I use SeaChem for Ca and lately for Mg. I prefer Salifert Mg, but same problem with availability.
People on the RC Chem forum talk crap on the SeaChem, saying that it reads low for Ca. I'm able to get the same readings with SeaChem Ca as others get with Salifert Ca. The thing to remember is to go to the bright blue endpoint with SeaChem.
I like the Salifert tips. I use them with my SeaChem kits. A drop out of a Salifert tip is ~.02 ml. You can do half drops at ~.01 ml pretty easily.
sfsuphysics
Supporting Member
Norman have you tried doubling up the water volume (or quadrupling) with the API test to increase the overall resolution of 1 drop, hence maybe see the first sign of color change a bit earlier? Which FYI is one thing I always wondered with those kits, is it when it first goes away from the "normal" color, or when it completely changes.
Mr. Ugly
Past President
I bought 3 kits with the intent to triple up on volumes.
I did a few runs doubled up on the sample size. It was ok. Even the Salifert test vial starts getting a little too full, and it was kind of a hassle going to 20-30 drops. I didn't bother with 3x sample size. Counting 40+ drops... eeesh!
API says to go to bright yellow endpoint, which ends up reading way high for me with this batch.
Anyway, use the Salifert syringe and tip. The lines are every .01 ml, and you can estimate to .005 ml. That's 8x resolution of the standard API method, and 4x the resolution of API's "more accurate" method.
You don't have to lose count of a crazy number of drops. Makes it easy to titrate and chew gum at the same time
I did a few runs doubled up on the sample size. It was ok. Even the Salifert test vial starts getting a little too full, and it was kind of a hassle going to 20-30 drops. I didn't bother with 3x sample size. Counting 40+ drops... eeesh!
API says to go to bright yellow endpoint, which ends up reading way high for me with this batch.
Anyway, use the Salifert syringe and tip. The lines are every .01 ml, and you can estimate to .005 ml. That's 8x resolution of the standard API method, and 4x the resolution of API's "more accurate" method.
You don't have to lose count of a crazy number of drops. Makes it easy to titrate and chew gum at the same time
Mr. Ugly
Past President
[quote author=Mr. Ugly link=topic=3011.msg34276#msg34276 date=1203405625]I use the API reagent with the Salifert syringe and tip. I don't use the dropper bottle. I use the large vial from the Salifert kit so I can mix while titrating. I stop titrating at the first hint of green, not yellow. And I take my endpoint to be .02ml(1 Salifert drop) less.[/quote]
Also, I use a 5ml syringe for measuring the water sample volume.
Also, I use a 5ml syringe for measuring the water sample volume.
tuberider
Guest
Norman did you use the new Salifert without the "two drops" it's a reddish/orange reagent. The reason I ask is that I have three Salifert kits that all read different. The new one with just the single step included a reference solution, which of course it matched, but it was from them and they can formulate it to match whatever they want. The new test kit reads a little lower than the old Salifert, and (of course) lower than the API, however I do have one salifert kit that matches the API, both API's I have read the same.
Thanks for all the work
Thanks for all the work
Mr. Ugly
Past President
Ok, I made 2 liters of 3.6 meq/L alk test standard using sodium carbonate monohydrate.
3.6meq/L X 50.04ppm CaCO3 X 124(Na2CO3*H20)/100(CaCO3) X 2L = 447 milligrams
So .447 grams of sodium carbonate to 2 liters of distilled water.
I'll see how the test kits read the standard.
If anybody wants some alk standard lmk. That is if I don't get some crazy numbers from it.
Same for the 35ppt refractometer standard I made a while back.
3.6meq/L X 50.04ppm CaCO3 X 124(Na2CO3*H20)/100(CaCO3) X 2L = 447 milligrams
So .447 grams of sodium carbonate to 2 liters of distilled water.
I'll see how the test kits read the standard.
If anybody wants some alk standard lmk. That is if I don't get some crazy numbers from it.
Same for the 35ppt refractometer standard I made a while back.
Thales
Past President
I can't wait to see your results with the standard. If you drop some off on my doorstep on your way to work, I'll try it with my Elos kits.
[quote author=Mr. Ugly link=topic=3011.msg34293#msg34293 date=1203433012]
API says to go to bright yellow endpoint, which ends up reading way high for me with this batch.
[/quote]
Thats weird. Most procedures for any alk titration I have read say go for the first stable color change, not to keep adding reagent.
[quote author=Mr. Ugly link=topic=3011.msg34293#msg34293 date=1203433012]
API says to go to bright yellow endpoint, which ends up reading way high for me with this batch.
[/quote]
Thats weird. Most procedures for any alk titration I have read say go for the first stable color change, not to keep adding reagent.
Mr. Ugly
Past President
Well, stable meaning that the color doesn't dissipate when you swirl the solution.
So during the transition from blue to bright yellow, the intermediate drops do varying shades of green that are stable during the swirling.
Right before you get the first stable green, you'll get a green that will go away after 2 or 3 swirls. That's how you know you're getting close to the endpoint.
So during the transition from blue to bright yellow, the intermediate drops do varying shades of green that are stable during the swirling.
Right before you get the first stable green, you'll get a green that will go away after 2 or 3 swirls. That's how you know you're getting close to the endpoint.