Alkalinity: Large discrepancy between Salifert and Hanna

[eddius_maximus]

I'm doing my weekly testing this morning and decided on a random whim to double check my alk readings. I typically use Hanna as it's easier and online opinion seems to agree that it's reliable.

Hanna reading: 8.1
Salifert reading: 7.3

This delta is causing me stress. I did both tests two additional times. Six tests total. The same reading each time (8.1 and 7.3).

For what it's worth, both bottles are nearly empty. I have more Hanna reagent coming in a couple days. Could that be a factor for the huge difference? If the Hanna is accurate, I'm good. If the Salifert is accurate, I'd much rather raise Alk to be at my happy 8 mark.

Please advise!

 

[SPR1968]

I'm doing my weekly testing this morning and decided on a random whim to double check my alk readings. I typically use Hanna as it's easier and online opinion seems to agree that it's reliable.

Hanna reading: 8.1
Salifert reading: 7.3

This delta is causing me stress. I did both tests two additional times. Six tests total. The same reading each time (8.1 and 7.3).

For what it's worth, both bottles are nearly empty. I have more Hanna reagent coming in a couple days. Could that be a factor for the huge difference? If the Hanna is accurate, I'm good. If the Salifert is accurate, I'd much rather raise Alk to be at my happy 8 mark.

Please advise!

You have to bare in mind that they both have margins of error and the Hanna is 0.3dKH or 5% as they are both ‘hobby grade’ kits.

I would just pick one and stick with it (I prefer Hanna for alkalinity), as stability is more important. Don’t get into chasing numbers as it will drive you mad

And welcome to R2R as well great to have you with us!

 

[ZoWhat]

Mines worse
Salifert 9.x
Hanna 11.x, sometimes 12.x

Hanna uses an optical eye to judge the color of the solution.

My question to Hanna is how many shades of color does it interrupt? Hanna claims 0.3dKH accuracy but that's in a lab with a perfectly new batch of triton media and a new calibrated optical eye

I personally think Hanna is quick to use but you lose a lot of accuracy. I'm sure people will disagree bc they are financially invested into Hanna.

I personally trust a drip test more




.

 

[eddius_maximus]

Don’t get into chasing numbers as it will drive you mad

Too late, I'm eating my shoes over here.

 

[squampton]

I don't do it often, but when I do both Hanna and Aquaforest alk test to compare they are usually pretty much the same, never far off from one another.

 

[eddius_maximus]

I don't do it often, but when I do both Hanna and Aquaforest alk test to compare they are usually pretty much the same, never far off from one another.

Oh good. So this is me now

 

[dwest]

I tested the difference between the two once. It as 0.3 dKH. I now use the easier one, Hanna.

 

[KrisReef]

Too late, I'm eating my shoes over here.

How do the corals look? If they are not happy then you are correct to be concerned. If they are looking normal then test three times.

If you get repeatable numbers, use that number as your target going forward as stability with healthy coral is the good number you want to use.
The accuracy can be off as long as the number is reliably repeatable.

Hope this helps.