red sea alkalinity test end color

[Archaic37]

On the card it shows a light.blue as the start and I can achieve that with the first .4ml. Now the end color on the card is like a orange gold. The end color i get no.matter how much I put in is a orange red. Any ideas?

[Archaic37]

http://i.imgur.com/XHbliB8.jpg

card color

 

 

http://i.imgur.com/PJAgLjR.jpg

 

Color I get (i can achieve a light pink at some point)

[markalot]

That's fine. you are looking for the change point, no need to match the color exactly.

[evo_2679]

+1- Should be a bronze / peach color .

[Archaic37]

Ah so as soon it changes from blue to a red thats it?

[NanoTopia]

This is funny because I have post out to Steve at RedSea asking the very same question. I have provided him with photographs of my colour changes as I added titrant. It is the weekend so I probably won't hear back until Monday. Here are the three pictures I sent. Some feedback from a different forum suggests #3 but from what I have read (below) from Kevin at RedSea I think it is #2. Anyway, I should find out what he says in a couple of days.

 

#1

 

 

#2

 

 

#3

From RedSea regarding End Point Colour for Alk,Mg,Ca titration.

Alkalinity. you are looking for a pink colour as opposed to an orange colour ( Dazza 1304 has posted some pictures in a thread started by Sheep600fx , picture 1 in post 6 is what you’re looking for and many thanks to Daryl for posting them) In fact the true end point of the KH test is one drop before the pink which is an almost colorless point which really is difficult to see. Since one drop of KH is equivalent to 0.15 dKH, (which is insignificant for aquariums) we decided to set the end point at the one drop passed the true end point as we thought that it is much easier to identify. Therefore look out for an almost colourless liquid in the vial and stop at the first sign of pinkness.

 

Magnesium . One of the important issues with the magnesium kit is being able to recognize the end point. When the blue end point is first reached is disappears very quickly. We write about this in the instructions but many do not fully understand the importance of this information. The blue color of the end point disappears and the liquid returns almost to the previous color. Most titrations maintain the end point when it is reached and therefore this is a very unusual instruction and differs from many other makes. Stop at the first sign of a blue liquid in the vial.

 

Calcium There doesn’t seem to be any concerns with identifying the end point on the Calcium test but for completeness, stop when you see a blue liquid in the vial.

[Archaic37]

Thanks nano, so I did thr test recording first sign of pink and a more red color. First sign of pink was 8.1 so lower than I.expected especially since the red sea coral pro salt mixes to 12.2.

 

I have just hit the point where I probably should start dosing. Calc is 460 and I want 475, mag is 1300 I want closer to 1400 and alk I want 9-9.5 instead of 8.1

[NanoTopia]

Your welcome, I will post what RedSea has to say as well here on this thread so you know for sure

[phineous]

My experience is that the alkalinity reagent oxidizes over time and the reagent and endpoint colors change. My reagent is now orange, and the endpoint is yellow. I've run the test side by side with a Hanna checker and an API test and the oxidized Red Sea test result is close to the others.

 

I'm kind of peeved with them that they don't admit this and put an expiration date on the Alk test. They also won't admit to problems with their Phosphate Pro test kit, and only reluctantly admit to bad reagent with the Calcium Pro test kit.

[markalot]

My experience is that the alkalinity reagent oxidizes over time and the reagent and endpoint colors change. My reagent is now orange, and the endpoint is yellow. I've run the test side by side with a Hanna checker and an API test and the oxidized Red Sea test result is still close to the others.

 

I'm still kind of peeved with them that they don't admit this and put an expiration date on the Alk test. They also won't admit to problems with their Phosphate Pro test kit, and only reluctantly admit to bad reagent with the Calcium Pro test kit.

 

I think it's due to the dye added to make it a 1 step kit. I prefer the Salifert for KH even though I have to do the extra step of adding dye.

[Eisernes]

This has been driving me crazy. I have been waiting for an end color for all three of these. I knew my levels couldn't possibly be that high just from salt.

[NanoTopia]

My experience is that the alkalinity reagent oxidizes over time and the reagent and endpoint colors change. My reagent is now orange, and the endpoint is yellow. I've run the test side by side with a Hanna checker and an API test and the oxidized Red Sea test result is close to the others.

 

I'm kind of peeved with them that they don't admit this and put an expiration date on the Alk test. They also won't admit to problems with their Phosphate Pro test kit, and only reluctantly admit to bad reagent with the Calcium Pro test kit.

Over what amount of time?

[NanoTopia]

This has been driving me crazy. I have been waiting for an end color for all three of these. I knew my levels couldn't possibly be that high just from salt.

Titration is a very complex thing, every reagent has it equivalence point. It is up to the manufacturer to indicate exactly what colour that it is. End point and equivalence are two different things...from Wikipedia http://en.wikipedia.org/wiki/Titration

 

 

Endpoint and equivalence point

 

Though equivalence point and endpoint are used interchangeably, they are different terms. Equivalence point is the theoretical completion of the reaction: the volume of added titrant at which the number of moles of titrant is equal to the number of moles of analyte, or some multiple thereof (as in polyprotic acids). Endpoint is what is actually measured, a physical change in the solution as determined by an indicator or an instrument mentioned above.^[25]

 

There is a slight difference between the endpoint and the equivalence point of the titration. This error is referred to as an indicator error, and it is indeterminate.^[26]

[phineous]

Over what amount of time?

 

About one year. The reagent started changing color soon after I got it. It could have been caused by a broken syringe tip, but I only used it three times before I stole a tip from another kit. I was getting air in the syringe from the broken tip, and returning the reagent to the bottle before submerging the tip deeper and drawing it up without air. The instructions say not to return unused reagent to the bottle, and Aviad posted over on their RC forum the reason was because the air bubbles would accelerate oxidation.

 

I bought a Hanna Alk checker shortly after so I've only used about half the Alk reagent in a years time.

[NanoTopia]

I would not trust reagents that have been exposed to air for more than 6 months.

 

About one year. The reagent started changing color soon after I got it. It could have been accelerated by a broken syringe tip, but I only used it three times before I stole a tip from another kit. I was getting air in the syringe from the broken tip, and returning the reagent to the bottle before submerging the tip deeper and drawing it up without air. The instructions say not to return unused reagent to the bottle, and Aviad posted over on their RC forum the reason was because of oxidation.

 

I bought a Hanna Alk checker shortly after so I've only used about half the Alk reagent in a years time.

[MikeTR]

#2 doesn't look pink enough, #3 looks like one or two too many drops.

[NanoTopia]

#2 doesn't look pink enough, #3 looks like one or two too many drops.

 

You see, this is not consumer friendly testing IMO. No definitive endpoint means +/- whatever.

 

 

Titration is accurate if you know the endpoint. Who does for sure? Only the makers

 

 

And, every drop changes the colour, so what is the end point? First sign of pink?

[MikeTR]

We'll now imma have to do a test lol. Standby

[MikeTR]

Ok so mine changes to like a grayish blue/purple just before it turns pinkish purple and that's when I stop. So you could say I stop at the first signs of pink. It took only an additional .03ml to turn it too pink. This is a small margin of error which equates to about .5 dKh. Fortunately for us being off by .5 dKh doesn't matter (unless you are teetering on 7) so getting the stop point exactly on the money isn't crucial. I don't really care if I'm at 9.2 or 8.7 as long as it's stable.

 

Just to be clear, I stop when it's pinkish not grayish. I'm tired is this making sense lol

[NanoTopia]

Confirmed from RedSea, this is the End Colour you should be looking for with the Alkalinity Pro Test Kit:

 

[Archaic37]

Ah good then that means my alk isn't 8.1 It is actually closer to 9.5. I will have to retest to make sure.

 

Thanks nano

[MikeTR]

Yes, i just switched from using baked baking soda to pH plus from the pool store (99.8% pure sodium carbonate) I'll have to keep an eye on my alk as the solution may be a little stronger.

[penfold2]

My experience is that the alkalinity reagent oxidizes over time and the reagent and endpoint colors change. My reagent is now orange, and the endpoint is yellow. I've run the test side by side with a Hanna checker and an API test and the oxidized Red Sea test result is close to the others.

 

I'm kind of peeved with them that they don't admit this and put an expiration date on the Alk test.

 

I agree. The color change on my Red Sea alkalinity kit matched the card for a while, but then the color shifted and now it's too difficult to tell where the endpoint is. So I went back to using a LaMotte alkalinity kit which has a tablet that you add for indicator dye, and the color change always matches the card.

[eolith]

Thanks for this thread. i'm struggling with my kit. My card shows Orange, and the color slowly changes to orange, not immediately. This is image here is the first switch to orange, and it's quite pale. The Orange on the card is much deeper, which i can get to with much more added. But it's certainly not a one drop sudden color change. This photo makes the fluid look more orange than the card, which is odd, because the card looks accurate.

 

 

[Eisernes]

Mine is orange too, not pink. Are we looking for that pale orange or the dark orange? There is a huge difference between the two. I do get that almost colorless stage talked about in Nanotopias post.