Salifert Alkalinity test(green) consistently below API(yellow)? Which one is right?

[furcifer208]

IO salt water tests at 10.2 (Salifert) and 11 (API).

 

[MTBake]

I'd trust the Salifert. I've used Salifert for over a decade with no issues.

 

[JimWelsh]

What do you mean by the "(green)" in your title? Please see Alkalinity titration endpoint pH & Salifert endpoint color.

 

[Hitman]

Salifert and it shouldn’t be green it turns blue in a Salifert test

 

[JimWelsh]

What do you mean by the "(green)" in your title? Please see Alkalinity titration endpoint pH & Salifert endpoint color.

Salifert and it shouldn’t be green it turns blue in a Salifert test

I give up.

 

[Justin Cook]

I think the subject line was referring to the color of the lines on the chart. Salifert is the green line and API is the yellow line.

Edit: It totally took me a minute too!

 

[JimWelsh]

I think the subject line was referring to the color of the lines on the chart. Salifert is the green line and API is the yellow line.

D'oh! Thank you.

 

[furcifer208]

Not trying to confuse or start controversy. Just trying to figure out how to use my test kits. Yes green refers to the attached data. Should IO be at 10 or 11 dKH? Salinity is 1.025.

 

[Justin Cook]

I've found Reef Crystals to be very inconsistent. I know you're asking about IO but Reef Crystals is an IO product and I assume it would fluctuate as well.

 

[furcifer208]

I've "returned" the Salifert kit on Amazon. They'll send me another one and I'll try that one for a tiebreaker. If it test's the same as the other Salifert kit then maybe I'll just keep both and stick with Salifert since I've heard "bad" things about the API kits.

 

[Justin Cook]

I've always used Salifert and never had any complaints. One thing that I always keep in mind is that these tests aren't really all that accurate. They work for our purposes but testing the same water a few times can render different results. A good test kit will be consistent enough for what we do and I certainly wouldn't expect a difference of 2-3 dKH like you're seeing between the two different brands but, overall, hobby grade kits are still hobby grade.

 

[furcifer208]

Update:
API 9dKH (yellow), 8 (greenish yellow), 7 (greenish), 6 (blue)
Salifert #1 6.7dKH
Salifert #2 7.3dkH

I'm going to call it 7 add 3mL of Randy's Alkalinity recipe #1 (baked Arm and Hammer). 14mL would get me from 7 to 9 dKH.

I also found this which was helpful to know. My API test is a bit old (purchased over a year ago) maybe it went bad? Expiration date is 6/2021
https://www.reef2reef.com/threads/b...i-hanna-triton-awt.234660/page-3#post-2754827

 

[Randy Holmes-Farley Verified Community Expert]

The API does not have good resolution. I'd stick with the Salifert and use the endpoint colors that Jim suggests are correct above.