KH/ Alk which to trust?

[legacy2mj]

Salifert test result - 8.9
Hanna - 7.8

Which to trust?

 

[UMALUM]

I don't have a hanna so I can't honestly pick between the two, but your results maybe closer than you think. If I'm not mistaken I read somewhere that the Salifert results should be gathered at the point the vile turns violet and not pink, red, orange, ect. If this is the case and you didn't take that adjustment into account then maybe they'll match?

 

[gbroadbridge]

Salifert test result - 8.9
Hanna - 7.8

Which to trust?

Depends on a couple of things.

The Hanna Alk reagent is only really good for about a month after opening - after 3 months it reads very low unless stored refrigerated - probably due to oxidation of the reagent.

The salifert test effectively never expires however as pointed out above, the titration endpoint is not when the sample is completely pink, but when it is halfway there - a purple color.

Used consistently, I'd put my money on the salifert.

 

[legacy2mj]

Depends on a couple of things.

The Hanna Alk reagent is only really good for about a month after opening - after 3 months it reads very low unless stored refrigerated - probably due to oxidation of the reagent.

The salifert test effectively never expires however as pointed out above, the titration endpoint is not when the sample is completely pink, but when it is halfway there - a purple color.

Used consistently, I'd put my money on the salifert.

Interesting. The Hanna test kit is pretty new. I would say 1 month old (to me)…. I did not know this about the color on salifert, I have stopped my dips at pink. So these results may be much closer than I originally thought. I use a mag stir device for my vials. So I will retry this comparison and stop the reading prior to a solid pink. Appreciate the response.

 

[TangerineSpeedo]

Couple things, Yes the reagent can get oxidized, but yours should be good, but yes I have seen it go bad.
Also if you are using a mag stirrer (Bless these little things) once you get the color, stop the stirrer and see if it stays that color. This goes with other tests like Calcium. This has been my experiences anyway.

 

[Borat]

Trust the number you like more..

 

[legacy2mj]

Couple things, Yes the reagent can get oxidized, but yours should be good, but yes I have seen it go bad.
Also if you are using a mag stirrer (Bless these little things) once you get the color, stop the stirrer and see if it stays that color. This goes with other tests like Calcium. This has been my experiences anyway.

I 100% agree. I notice this the most with my Mag test. I have learned to let things work for a few seconds before continuing with that. But I will make an effort to do this “pause” technique with the others and see how things differ. Luckily I do monthly ICP tests, so I would know if things are way out of bounds. Just want to maintain the most consistency inbetween. Since I don’t run a controller of any kind it’s up to me and diligence to keep an eye on it all.

 

[Pod_01]

Salifert test result - 8.9
Hanna - 7.8

Which to trust?

So do 3 test with Salifert and 3 test with Hanna. Average all results and that is your number….

Since the two are within 1dKh I say your value is 8.4…. and call it a day. 8.4 dKh is good in my book and so is 8.9 and 7.8.

You can get two more tests kits to really have some fun with statistics.

Good luck,

 

[Randy Holmes-Farley]

I 100% agree. I notice this the most with my Mag test. I have learned to let things work for a few seconds before continuing with that. But I will make an effort to do this “pause” technique with the others and see how things differ. Luckily I do monthly ICP tests, so I would know if things are way out of bounds. Just want to maintain the most consistency inbetween. Since I don’t run a controller of any kind it’s up to me and diligence to keep an eye on it all.

I personally do not think turning off the stirring makes chemical sense, but allowing time for each drop of titrant to chemically react before deciding if more is needed is important.

 

[dwest]

It doesn’t really matter if you run your tank at 8 or 9 dKH. Pick a test kit and try to keep alkalinity consistent.

I used salifert for many years and now use Hanna for convenience and my reducing ability to see color changes well.

 

[Dragen Fiend]

I go by salifert for almost all tests I've found them to be the only consistent tester.

But hanna is close enough where I would still feel safe if I ran out of salifert.

Yesterday mine was
hanna- 7.9
Salifert 8.1
seachem- 7.8

My alk is usually stable between 7.9-8.1

The lowest I've seen it drop was 7.5 on the hanna.

 

[TangerineSpeedo]

I personally do not think turning off the stirring makes chemical sense, but allowing time for each drop of titrant to chemically react before deciding if more is needed is important.

For example: If I am doing a titration test for CA and introducing reagent a drop at a time when the solution goes from pink to blue. If I stop to mixer at that time the solution will turn back to pink. It is usually one or two drops after that that it stays blue.
So yes I agree with you that the reagent needs time to react but something with the spinning of the solution gives it a early false positive. Give it a whirl (pun intended) see if you have the same results...

 

[Randy Holmes-Farley]

I’m just saying that the only effect of stirring on chemistry is to make and keep the solution homogeneous. Stirring will never slow any ordinary reaction, and it never causes things to happen that don’t already happen without stirring.

 

[michigan-reef]

I personally trust the Salifert test. I would do three separate tests with the Salifert to make sure you are performing the test the same every time, if so just trust it.

I have bought two Hanna checkers, one failed after about a year and I don't trust the other one anymore. I do believe they were accurate when they were new.