Red Sea pro alk

nstd · Dec 4, 2015

My alk test kit turns yellow instead of red. Is the test kit bad or is the change color still an accurate reading?

Randy Holmes-Farley · Dec 4, 2015

It turned from blue to yellow without passing through the recommended pinkish color?

At what alkalinity did it turn yellow?

joshkirkland83 · Dec 4, 2015

Randy Holmes-Farley said:
It turned from blue to yellow without passing through the recommended pinkish color?

At what alkalinity did it turn yellow?

I know red sea says pinkish, but the card says a red color. Is the dark pink color the final color?

Randy Holmes-Farley · Dec 4, 2015

It's hard to describe the color and pink isn't the best term (IMO), but their video shows it:

http://www.redseafish.com/reef-care-program/reef_foundation_program/kh-alkalinity-pro-test-kit/

PedroYoung · Dec 4, 2015

FWIW, I have some red/green color blindness and the Red Sea Alk test was impossible for me to read. I found the Salifert had better contrast in the color change on the Alk test.

nstd · Dec 4, 2015

Thank you everyone for relying. I took some pictures of the different color changes during the alkalinity testing process.

First picture is the initial BLUE
Second picture is the first change at 7 dKH
Third picture is the 2nd change at 7.8 dKH
Fourth picture is the 3rd change at 8.4 dKH

After the fourth picture color does NOT change even after emptying 1 ml of solution.
The pictures are pretty accurate to what I see.

kbourque · Dec 4, 2015

That's odd how old is the test kit

kbourque · Dec 4, 2015

And to confirm you only only have tank water and the red alk solution in there?

twilliard · Dec 4, 2015

I do have to add..
I have dealt with red sea about this exact issue.
I got to the point where I could tell before even opening the bottle the end result would be orange.
I would send it back for a replacement.
The one bottle I do have is batch 743
It turns orange.
Haven't used it for a year now.

redfishbluefish · Dec 4, 2015

Looking at the syringe of titrant, it appears more orange then usual. I'm wondering if the mother solution of titrant isn't contaminated. Good Laboratory Practices require that no extra titrant be returned to the mother solution. That is, when you're done with the titration, and you've gotten the color change you needed, and have taken the reading, simply squirt the extra titrant into the titration sample bottle, to be dumped and washed out. DO NOT return any extra to the stock solution of titrant.

The second point, with any colorimetric titrations, you're simply looking for the color change from one color to another. This isn't like the API tests were you're trying to match the color in the bottle with the color on a card. Again, simply a color change for these types of titrations....not necessarily matching the exact color on the card.

Hope this helps

Perculap · Dec 4, 2015

I abandoned my Red Sea Alk kit. The color of the water NEVER matches the color of on the card.
My tests always turned yellow. Card is Orange. The only way to get to Orange(or red, whatever color that is lol) was to use 1.5ml+ of regeant.
After months of inaccurate tests and STN, I finally realized that the first yellow color is the result and it never reaches orange. I got a hanna how and couldn't be happier.

Randy Holmes-Farley · Dec 4, 2015

What if you add more titrant past that yellow color. Does it ever get red?

Perculap · Dec 4, 2015

Randy Holmes-Farley said:
What if you add more titrant past that yellow color. Does it ever get red?

I don't know if it ever gets red, it looks more like a dark orange to me. I have to use about 1.5ml of regeant to get to that color. I finally discovered the error because I bought a Seachem test kit and was getting about 2.5-3.5meq/l. That had me really scratching my head. Finally got a Hanna and it always in the same range as the seachem test, 2.5 - 3.5meq/l or 7-9dkh (I am just rounding the conversions I don't have exact numbers with me atm).

When I get home, I'll try to make a video or take pics.

Perculap · Dec 4, 2015

nstd said:
Thank you everyone for relying. I took some pictures of the different color changes during the alkalinity testing process.

First picture is the initial BLUE
Second picture is the first change at 7 dKH
Third picture is the 2nd change at 7.8 dKH
Fourth picture is the 3rd change at 8.4 dKH

After the fourth picture color does NOT change even after emptying 1 ml of solution.
The pictures are pretty accurate to what I see.

My test kit is the same way. I found a youtube video of a guy discussing this same exact issue. Some new batches match the color correctly apparently.

Randy Holmes-Farley · Dec 4, 2015

FWIW, you can use a pH meter to judge the endpoint. The titration is completed at pH around 4.2-4.5 (depends a bit on the actual alkalinity and other factors). That can be a lot more accurate than looking for a color change.

I discuss that here:

A DIY Alkalinity Test: By Randy Holmes-Farley
http://www.reefedition.com/a-diy-alkalinity-test-by-randy-holmes-farley/

You can also use a hybrid, where you use the pH to determine the exact color to look for, then always use that exact color.

joshkirkland83 · Dec 4, 2015

nstd said:
Thank you everyone for relying. I took some pictures of the different color changes during the alkalinity testing process.

First picture is the initial BLUE
Second picture is the first change at 7 dKH
Third picture is the 2nd change at 7.8 dKH
Fourth picture is the 3rd change at 8.4 dKH

After the fourth picture color does NOT change even after emptying 1 ml of solution.
The pictures are pretty accurate to what I see.

No he is using the ph/alk test. Not the 3in1 foundation test. Those are the correct colors. Yellow is overdose.

joshkirkland83 · Dec 4, 2015

This is what hes using. You want the green color.

Sabellafella · Dec 4, 2015

twilliard said:
I do have to add..
I have dealt with red sea about this exact issue.
I got to the point where I could tell before even opening the bottle the end result would be orange.
I would send it back for a replacement.
The one bottle I do have is batch 743
It turns orange.
Haven't used it for a year now.

I have a batch that reads orange but its on point with my nyos and old redsea test kit, is orange supposed to be bad?