Is it important which test kit is right (Salifert vs Hannah) when the numbers differ substantially?

[kdx7214]

Today I received my Salifert test kits after having some issues with sps dying. I decided to test the two against each other for alkalinity. Hannah showed 8.2 while Salifert showed 7.75. Is it important to know which is more accurate or is it better to look for the number staying the same? I've had the Hannah reagent in the refrigerator as recommended on here and all reagents are within date.

 

[FishLvR]

That's tough? Which sample tastes better? That's the one I would go with.

 

[KrisReef]

If the numbers have been stable over time then the question of which one is most accurate is not that big of deal since the difference is fairly small between the two.

That aside, I find it irritating that our test kits can give us numbers but most of us can’t tell which one is correct, or if they are both wrong and perhaps both are way off.

 

[Pod_01]

Hannah showed 8.2 while Salifert showed 7.75

Just my opinion but I would average them and assume Alk is approximately 8 dKh. Otherwise you are going to go mad since they will never match.
You can redo the test with each one 3x and see what you get… always fun experiment.
Just to confuse yourself further get another test kit…

From my point of view if the reading between two kits is within 1 dKh I call it success.

Also stability is critical, the delta between them not so much.

Good luck,

 

[Randy Holmes-Farley Verified Community Expert]

Today I received my Salifert test kits after having some issues with sps dying. I decided to test the two against each other for alkalinity. Hannah showed 8.2 while Salifert showed 7.75. Is it important to know which is more accurate or is it better to look for the number staying the same? I've had the Hannah reagent in the refrigerator as recommended on here and all reagents are within date.

I personally do not think reef tanks require a highly specific alk number, so if either test is reproducible, then that should be adequate, IMO.

 

[SpyC]

How many tests did you run? Was it only one of each? If it was, you could test 3 times on each then avg them base on kit.

 

[Waters]

I can tell you my Hanna ALK meter reads exactly .8 higher than any other test that I have used. I always subtract that amount whenever I test with that meter.