Salifert Alk test

[Ktran350]

Hello all,

Doing a water change today with Red Sea Blue bucket. Salinity is at 1.025 and temp is at 76 degrees. I am testing my water change now and for the Salifert Alk rest I am getting 8.6 dkh. However, with the test it changes from “pink” to a clear greenish tint like 30 seconds later. Did the test 3x and Alk is at 8.6 all 3x and the test vial turned that greenish color all 3x. Never happened before. Test expires 5/23. Anyone have any input?

 

[TeotheCoral]

Hello Mi’t brother. How’s the salifert compared to the Hanna for alk?

 

[Dan_P]

Hello all,

Doing a water change today with Red Sea Blue bucket. Salinity is at 1.025 and temp is at 76 degrees. I am testing my water change now and for the Salifert Alk rest I am getting 8.6 dkh. However, with the test it changes from “pink” to a clear greenish tint like 30 seconds later. Did the test 3x and Alk is at 8.6 all 3x and the test vial turned that greenish color all 3x. Never happened before. Test expires 5/23. Anyone have any input?

I think the test solution is losing carbon dioxide, making the solution less acidic and reversing the titration.

 

[Randy Holmes-Farley Verified Community Expert]

I think the test solution is losing carbon dioxide, making the solution less acidic and reversing the titration.

CO2 loss (and high starting CO2) doesn't impact the real alk, but I am concerned it may alter the Hanna methodology.

 

[TeotheCoral]

Randy are you a real chemist my coral bro?

 

[Ktran350]

Hello Mi’t brother. How’s the salifert compared to the Hanna for alk?

Can’t say. I never used Hanna

I think the test solution is losing carbon dioxide, making the solution less acidic and reversing the titration.

How would the test kit lose carbon? I just retested a few hours later and it looks like it’s hilding the pink color (end state). I’m retiring the test kit back to Amazon and getting a new one regardless.

CO2 loss (and high starting CO2) doesn't impact the real alk, but I am concerned it may alter the Hanna methodology.

I’m not tracking. What do you mean?

 

[Potatohead]

Randy are you a real chemist my coral bro?

There is a reason the Chemistry forum is named after him

 

[JimWelsh]

Randy are you a real chemist my coral bro?

You're new around here, aren't you?

 

[TeotheCoral]

Yes and remember I’m just a coral like my friend JoeTheCoral so not too much brigh (?spelling)

 

[Randy Holmes-Farley Verified Community Expert]

Randy are you a real chemist my coral bro?

yes. pHD in chemistry from Harvard, decades of chemistry research...

 

[Randy Holmes-Farley Verified Community Expert]

I mean I worry that the Hanna methodology may not give accurate answers for seawater alkalinity when the CO2 level in the water is very high. They say it does and it might well be correct, but I personally would not rely on that fact without some sort of independent validation.

Do you know, Jim?

 

[TeotheCoral]

yes. pHD in chemistry from Harvard, decades of chemistry research...

You must super dupper smart. I heard grad students, at least in biochemistry my field from coral university, have to make their own reagents