Who do you trust for alkalinity?

[forestsofkelp]

I get wide variations, consistently, on my alkalinity.
My hannas will read 8.7. My GHL KhD (which I do calibrate from time to time but not as often as I should) will read 7.1. My ICP test will read 7.7.

I tend to trust my Hannas.
My khD will sometimes read close to hanna, sometimes off by about by a bunch (reliably) for 3-6 months, even after calibration. I basically tend to use it to just check for swings, as long as its always the same number, I am ok

My ICP always reads about 1.5 dkh lower than Hanna, and I cant tell why. I dont trust it because the sample is old and I think that can change the dKH

I just shoot for a 9.5 only hanna, so that I am either in the mid to high 8 range, or the mid 9 range. I dont put too much stock in KhD anymore as I am always worried there is a weird bub

However this is very annoying as I cant tell what my "true" dkH is and it ends up using a lot of reagent and it bothers me the numbers are off by so much.

Does anyone else have the same issue? It seems too wide for normal variation. Just trying to figure out if I have bad technique. Its been an issue for about a year (tank looks fine, any issues aren't from alkalinity)

 

[exnisstech]

I use one device, Hanna and just try and keep it consitant.

 

[graihg]

Don't get me started with the pH calibration...

But, I've noticed sailfert consistently reads 1 to 1.5 dkH lower than Fritz for alk.
I just bought a Hanna alk...waiting on it.

 

[forestsofkelp]

Don't get me started with the pH calibration...

But, I've noticed sailfert consistently reads 1 to 1.5 dkH lower than Fritz for alk.
I just bought a Hanna alk...waiting on it.

haha I use Hanna and a GHL KHD (which needs to be regularly calibrated).
Ive basically decided to use the Hanna weekly as my source of truth, read the KHD in relation to that, and use that to make sure there aren't wild swings...although that sometimes tends to read wrong if it gets a bubble or something.

Sometimes i can get the KHD and Hanna in sync, but not always. I think the KHD works great if you have the time to maintain it so you KNOW it is right (eg calibrate the probe every 1-2 months, use calibration fluid monthly, change the tubing regularly etc)