Dkh test kits

[Chipp]

i have been testing dkh with salifert. I decided to send in an ati icp test on the same day (12/20/2018) i tested my parameters with my salifert kits. When i got the icp results back it had dkh test on it and it was 7.3. I looked at my salifert reading from that same day and my dkh was 8.3.

I bought a hanna dkh test kit a few weeks ago and and got a reading of 7.6 vs the salifert at 8.3. So i bought a red sea test kit and just tested all three and got the following readings.

Salifert 8.6
Hanna 7.6. It always seems to read 7.5 or 7.6
Red sea pro 7.3

I’m not sure if the test kits all just suck or i am doing it wrong. Does anyone else use different kits and get all different readings?

 

[Dr. Reef Verified Sponsor]

i would get calibration solution for hanna and make sure it reads consistent. once that is confirmed then stick to the reading it gives and try to shoot for more consistent stable readings over days/weeks rather than a consistent number.
For example if alk is 7.5 on day on and 7.6 day 2, day 3 =7.5 , day4 = 7.5 etc
it may fluctuate a little but as long as you are within that range say 7.4-7.6 (example) you will be fine
No 2 tests results are the same. same sample in hanna will show 2 results as well in my experience.
This happens due to the kits margin of error or window of accuracy in which hanna has 0.05+or-

 

[dwest]

i have been testing dkh with salifert. I decided to send in an ati icp test on the same day (12/20/2018) i tested my parameters with my salifert kits. When i got the icp results back it had dkh test on it and it was 7.3. I looked at my salifert reading from that same day and my dkh was 8.3.

I bought a hanna dkh test kit a few weeks ago and and got a reading of 7.6 vs the salifert at 8.3. So i bought a red sea test kit and just tested all three and got the following readings.

Salifert 8.6
Hanna 7.6. It always seems to read 7.5 or 7.6
Red sea pro 7.3

I’m not sure if the test kits all just suck or i am doing it wrong. Does anyone else use different kits and get all different readings?

I would expect that kind of range with hobby grade test kits. When I compared my Hanna and salifert, they were different by 0.5 dKH. My batch to batch difference with Hanna solutions seems to be about 0.3.

 

[JimWelsh]

There has been much discussion online about the correct endpoint color for the Salifert alkalinity test kit. I attempt to answer that question in this thread.

 

[Chipp]

There has been much discussion online about the correct endpoint color for the Salifert alkalinity test kit. I attempt to answer that question in this thread.

Thanks Jim! That was awesome! I always jotted down four different color changes I would see and it was the blue voilet, violet, violet pink and pink. If i go by the article color it would put me at 7.7 with salifert which Is right at the hanna reading. The red sea i only did twice, but is close enough to be a miss read on the color by me.

 

[ckalupa]

I use the Hanna most times now. Have also seen variance between it and Red Sea. Pick one. Not that significant of a difference. I have Hanna’s control vials and it reads within range in the control. I like that with the Hanna you do not have to interpret a color change.

 

[PatW]

For me Hanna and Red Sea are pretty close with Red Sea maybe reading a tad bit lower. And that lower reading might be my interpretation of the end point. I like Hanna because the reading is digital. With Red Sea, I figure the end point is a green with a yellow tint rather than a blue tint. And the interpretation of the end point is a bit imprecise feeling