Salifert testing higher dKh than Hanna

WhiskeyCoffee · 02/13/2018, 09:04 PM

So the other day I got some erroneous readings on my Salifert alkalinity test. First one was 9.6 dKh then two days later it was 12. I also tested a fresh batch of Reef Crystals and it came out 12 dKh. I panicked but everything looked healthy in my tank. Maybe I just screwed up the tests. I asked a buddy if I could borrow his Hanna and he said no prob. This is where it gets interesting. With the Hanna, I got:

Tank: 8.4 dKh
Reef Crystals: 11.0 dkH

So I decided to do another test with the Salifert tonight. Being as precise as possible, I got:

Tank: 9.5 dKh
RC: 12.0 dKh

Is this normal? I have about 3/4 of the Salifert test solution left so I'd hate to find out it's off. I know both tests are subject to human error but I've repeated the tests and got similar numbers all around.

thegrun · 02/13/2018, 10:32 PM

You might try to get a hold of some standard alkalinity solution. Salifert used to provide a standard in their test kits. Honestly I would be more inclined to trust the Salifert results the the Hanna. Also when you test the water with Salifert you need to add an extra drop or two to make the color change fully, you may not be adding quite enough titration solution. Doing so would make the test results very close to one another.

02/13/2018, 09:04 PM	#1
WhiskeyCoffee Registered Member Join Date: May 2016 Posts: 98	Salifert testing higher dKh than Hanna So the other day I got some erroneous readings on my Salifert alkalinity test. First one was 9.6 dKh then two days later it was 12. I also tested a fresh batch of Reef Crystals and it came out 12 dKh. I panicked but everything looked healthy in my tank. Maybe I just screwed up the tests. I asked a buddy if I could borrow his Hanna and he said no prob. This is where it gets interesting. With the Hanna, I got: Tank: 8.4 dKh Reef Crystals: 11.0 dkH So I decided to do another test with the Salifert tonight. Being as precise as possible, I got: Tank: 9.5 dKh RC: 12.0 dKh Is this normal? I have about 3/4 of the Salifert test solution left so I'd hate to find out it's off. I know both tests are subject to human error but I've repeated the tests and got similar numbers all around.

02/13/2018, 10:32 PM	#2
thegrun Registered Member Join Date: Dec 2008 Location: Garden Grove, Ca Posts: 17,023	You might try to get a hold of some standard alkalinity solution. Salifert used to provide a standard in their test kits. Honestly I would be more inclined to trust the Salifert results the the Hanna. Also when you test the water with Salifert you need to add an extra drop or two to make the color change fully, you may not be adding quite enough titration solution. Doing so would make the test results very close to one another.