lamotte alkalinity help

[empireinc00]

Hello,

I just purchased the lamotte alkanity kit. I'm wondering how do I determine the end point. Should I stop when the color start changing to purple or I should continue adding the drop till it dark purple? i'm really confused. please help.

Thanks.

[Mavrk]

<a href=showthread.php?s=&postid=11924677#post11924677 target=_blank>Originally posted</a> by empireinc00
Hello,

I just purchased the lamotte alkanity kit. I'm wondering how do I determine the end point. Should I stop when the color start changing to purple or I should continue adding the drop till it dark purple? i'm really confused. please help.

Thanks.

You stole my question :D

I have been getting lower readings with this kit and I want to know when to stop as well. I do know that if it goes red, then it is past the endpoint.

[PSam]

When it's a nice purple, and then 1 more drop makes it orangey-purple, that's what I call endpoint. When that 1 drop gives it a little orange/pink tinge, I count back 1 mark (4ppm).

[Boomer]

End Point is End Point. It means when there is a change in color you are at the End Point. You DO NO keep adding until it gets x y or z darker purple.

Should I stop when the color start changing to purple

So yes :)

[HBtank]

<a href=showthread.php?s=&postid=11926152#post11926152 target=_blank>Originally posted</a> by PSam
When it's a nice purple, and then 1 more drop makes it orangey-purple, that's what I call endpoint. When that 1 drop gives it a little orange/pink tinge, I count back 1 mark (4ppm). I do the same.

The directions have the three colors on the card. When I think it gets to the middle color, or the "endpoint" I mark that number. I then add one or two more drops to get the third color, to verify. You need to be just before the final color change to be at the "endpoint" , at least after many tests this is what my eyes tell me.


I find the middle color does not come in one quick change, and generally needs a few drops after it first starts to change from teal to purple..

I may be wropng, but it is not as simple as boomer said, the Lamotte kits do not have a sudden change with one drop. They have a much more gradual change and color matching is essential. The presense of a third color is unique and from my understanding it is there to allow you to be able to get to the correct shade of purple and still be able to verify you did not go to "far"..

With a good flourecent lamp or daylight, and the color card, you can easily match the endpoint color, and I like the last color change for verification...

I find it to be the best kit, but it does need a bit of skill and getting comfortable with..

[Billybeau1]

I've had problems with the color end point, but purple is purple.

The first drop that produces purple is supposed to be the end point.

My LaMotte tested lower than 4 other kits. :(

www.reefcentral.com/forums/showthread.php?s=&threadid=1306841&highlight=Elos

[HBtank]

Billy,

But the kit does indeed have a three color card for matching.. One for the start, one for the endpoint, and one for going "to far".. It implies a less than "distinct" change.

I might call Lamotte on this, but I think this is why you may be testing low. I have always tested this way and it matches all my other kits, AP and salifert.

Why have a third color if all you need is the first change in color?

I use a 6k light, and there is a BIG difference between the first color change and when it matched the middle color on the card. Under good light it is pretty obvious to me.

Additionally, I would say it needs about 5-10 drops to get from the initial change to the "to far".... Why would lamotte make the kit do this is all we need is the first change?

[Billybeau1]

Then why do they say purple is the end point ?

Purple is purple. :confused:

I do not like that test kit. Simple as that. :)

[Boomer]

HB that is fine to do it that way for verification. But any color change is EP. Next time take a piece of white paper and place the tube on it or behind it and you will see the color change much better. It is best to put the tube on top of the white page and view it from the top down through the length of the tube if possible.

[HBtank]

I do. I am very careful with my lighting and background. And the first change is not close at all to the color on the card IMO. And like I said above, many drops are needed to get to the third color.

Purple is not purple.. I might just take some pictures tomorrow and take better notes on the exact drops I needed to reach each color.

[Billybeau1]

Purple is not purple :confused:

[HBtank]

The color it first changes to does not match the card. A slight change to purple does not mean it matches the purple on the color card provided. You said why do they "say" purple.. well they say to reference the color card, and they show it... And I think this is not by accident.

If you could point me to another titration kit that has a color card, I might be more apt to jump on the sudden change bandwagon.

Anyways, I am not about to beat my head against the wall here. I agree the kit is much more of a PITA than my API. I just think it is more accurate, when needed.

I will mess with it tomorrow, with my camera, and post 1000's of words at a time, as this is getting tedious.

Remember, I am matching other kits, and you are testing low...

[Billybeau1]

The alkalinity test kits I use do not have a color card, and in fact I think it confuses the consumer even more.

Salifert, Elos, API and even Seachem show a distinctive color change and that is the end point.

I've had no problem with those.

If LaMotte has a different set of rules, they should point that out in their instructions.

[HBtank]

Maybe more distinct changes lowers accuracy. It certainly seems plausable to me. Using different reagents may get you a greater color change, but less clarity..

A distinct change may increase ease of use for the user, but sacrifice the clarity of the test itself.

By having a slightly more gradual change, you may get more accuracy and clarity.. But yes, then it relies on the eyes and is a PITA.. Believe me, I hate color cards, and is why I got my Hanna ;)

Anyways I do not know. I am only going on the premise that Lamotte is the most accurate, as I researched quite a bit and this was the conclusion, by far. I know you dislike the kit.. it was the most touted kit. Elos was second. "Old Salifert" third. I researched with Hach, but they do not work in SW.

Anyways, I still vote API #1 overall, it gives me what I need the quickest and easiest. i use it by far the most. :)

[Billybeau1]

<a href=showthread.php?s=&postid=11926632#post11926632 target=_blank>Originally posted</a> by HBtank
Anyways, I still vote API #1 overall, it gives me what I need the quickest and easiest. i use it by far the most. :)

At least we agree on something. :D

[packer]

I just got a lamotte yesterday as API was to vague for me and after my salifert problems I wanted a decent precise reading. After three tests I must say I like it. I dont think the few drops from the first purple to the past endpoint color really make that much difference, only 8ppm give or take.

[empireinc00]

I notice after it started to change color, I only had to add about 2-3 drops to get it to purple as the card shown. I compare color to the white part on that card to verify. If I add 2 more drops then it changed to something else. Maybe that's really the endpoint. The test did match my Elos test kit so I think I'm going to stick with that. Elos is much much easier but It's not that precise. I will install the calcium reactor next week so I need something a little more precise.

[Mavrk]

Some of the API tests discuss an intermediate color change. For instance, the calcium test says "the color will usually change from pink to purple before finally changing to blue." If you mix pink and blue, you get purple. So I don't see why Lamotte would be any different. The initial "purple" is a different shade than the card because it is a mixture of purple and teal (which is purple, just a different shade). So in this case, it is not whether purple is or is not purple, but rather that the initial purple is not what is shown on the card. If they had made the "too far" color the endpoint I think that would have been easier.


<a href=showthread.php?s=&postid=11926663#post11926663 target=_blank>Originally posted</a> by packer
I just got a lamotte yesterday as API was to vague for me and after my salifert problems I wanted a decent precise reading. After three tests I must say I like it. I dont think the few drops from the first purple to the past endpoint color really make that much difference, only 8ppm give or take.

8 ppm is almost half a point difference in dKH (0.448 to be precise). While I agree that this much difference does not matter in the long run, it is the whole reason to use lamotte over API (or Elos).

That said, when I compare it to my API test, your results make sense. I got 138 ppm as the begging color change. This equates to 7.728 dKH. With my API, I got 9 dKH. If the number is really about 8.176 dKH, then that would make sense since the dKH for API is in 1 dKH increments. Since the color changed so drastically with the 9th drop of API, I would normally interpret that as an 8.5, but really it just means that it is above 8 and at or below 9.

[packer]

Yeah I have both kits. Quick check with API but fine tune with the lamotte now. They both work great to keep your alk in the "zone" but Salifert made me anal in my testing so was frustrated with only 1dkh variables. Wish saliferts did not go belly up, or should I say things in my tank with my last kit testing almost 3dkh higher than reality.

[Billybeau1]

I will try my LaMotte a few more times and see if it is more accurate trying to match the color on the card. I'm testing 2 more salts today so we shall see. :)

[Mavrk]

<a href=showthread.php?s=&postid=11926564#post11926564 target=_blank>Originally posted</a> by HBtank
The color it first changes to does not match the card. A slight change to purple does not mean it matches the purple on the color card provided. You said why do they "say" purple.. well they say to reference the color card, and they show it... And I think this is not by accident.

If you could point me to another titration kit that has a color card, I might be more apt to jump on the sudden change bandwagon.

Anyways, I am not about to beat my head against the wall here. I agree the kit is much more of a PITA than my API. I just think it is more accurate, when needed.

I will mess with it tomorrow, with my camera, and post 1000's of words at a time, as this is getting tedious.

Remember, I am matching other kits, and you are testing low...

That would be cool if you could post those pics. I think it would be very helpful. Thanks.

[bdare]

I totally agree with HB. The color shift with the LaMotte kit is VERY gradual and not very distinct. I agree that making note of the color and ppm when you THINK it's right then add a few more drops. The only disticnt color change with that kit is when it goes from purple to red. Therefore, but subtracting 1-3 drops after it turns red I find the results to be very consistent with API and my OLD salifert ALk kit.

I also do most of my testing with API and every so often double check with LaMotte.

[PSam]

I got comfortable with LaMotte's endpoint by using results for API, Sali & ELOS, which all corroborated each other. Knowing that those 3 tested ~6.5 dkH, figured that value in ppm and watched carefully when I got near that ppm on the LaMotte syringe. Made it easier to kind of see the changes when close / too far.