Test kit problem Hanna vs Redsea vs two part ALK change.

[JAC-]

Hello friends,

I've found myself in a bit of a situation. I recently picked up a Hanna Alkalinity tester and have been using it for about two weeks. I was previously using a Redsea test kit.
I have a hard time seeing the blue - green color spectrum (been told I'm color blind, but that's a different story and an amusing one as I'm a EE for a living) that's why I switched to the Hanna. For the first 5 days I used both test kits to gain confidence in the new Hanna, they were both agreeing with in .2 DKH or so, so I felt good about the new tester. I've been wanting to change my 2 part because the Seachem reef builder I was using before didn't mix well and seemed to mix weak. Having the new tester that I could easily read, I decided it was time. I switched to using the BRS sodium bicarbonate mix.

Everything was going great until...


Tonight I was testing and for the second night in a row my alk was testing @ 10 DKH (yes I run it high) without me adding any alk last night it was at 10.2. Typically I've had to add daily to maintain anywhere near 10 DKH. I was suspicious so I tested with the Redsea kit. It showed 8.4 DKH. I tested 3 times with both and got the same results High Hanna low Redsea with each kit within .1 DKH of the previous respective tests. I tested both kits with my DI water and the came up 0. I did a 50% dilution with both and the results were 50% less that the original results.

Which kit do I believe? Any ideas for testing which kit drifted? Some of my corals are looking less happy so I'm inclined to think the Redsea is correct, but I also changed my alk mix because I'm impatient and apparently secretly desire chaos.

Any help is appreciated, laughs too because if it's all hitting the fan in a handbasket, we may as well have a chuckle for the trouble.

 

[JAC-]

Just discovered that Hanna makes a testing standard. So I'm ordering one. It'll be about a week before it arrives so any ideas for the short term would still be appreciated. I'm going to see if I can figure out an amount of bicarbonate to add to DI water and make my own standard today.

 

[X-37B]

My Hanna unit can vary as much as .8 from bottle to bottle.
I use 2 others.
Salifert and Elos to verify.
I run 7dkh.
Today both salifert and Elos read 7.0
Hanna reads 134 or 7.5.
Salifert is easy to read as its not color driven.
I use Hanna daily and know that on this bottle it reads higher than the other 2.
My testing standard is always within range

 

[jsker]

I have found that I test more consistent with the Hanna checker, buy using a new tip with each test. I ran into non consistent numbers awhile back and was frustrated.

I started experimenting with different syringes, tips for all the checkers. I ended up purchasing a 10 ml/1000uL pipe and tips to use with my test now. I also use new syringes with every test. I even went a step further and purchased a 10 ml/10,000uL pip and tips for a more accurate sample. It is a real pain to measure the amount of sample correctly in the cuvette.

I have not had any issue, except me not testing correctly. Or operator error by not following the procedures when testing

I clean my cuvettes in the dishwasher, then rinse the cuvettes with distilled water before each testing.

The key is to have everything clean that will be used for testing, without reschedule old sample water and dried reagent in the tips or syringes.

I hope this helps

 

[JAC-]

I have found that I test more consistent with the Hanna checker, buy using a new tip with each test. I ran into non consistent numbers awhile back and was frustrated.

I started experimenting with different syringes, tips for all the checkers. I ended up purchasing a 10 ml/1000uL pipe and tips to use with my test now. I also use new syringes with every test. I even went a step further and purchased a 10 ml/10,000uL pip and tips for a more accurate sample. It is a real pain to measure the amount of sample correctly in the cuvette.

I have not had any issue, except me not testing correctly. Or operator error by not following the procedures when testing

I clean my cuvettes in the dishwasher, then rinse the cuvettes with distilled water before each testing.

The key is to have everything clean that will be used for testing, without reschedule old sample water and dried reagent in the tips or syringes.

I hope this helps

Thanks friend,

That is some good information and I think I will be incorporating some of your suggestions.
It also sounds like you may be suggesting the Hanna may be more suspect of giving wrong results.
Or am I reading to far between the lines there?

Unfortunately, both test kits are testing repeatable just one or both of them is quite wrong.
They were originally aligned, so one did drift. If I can figure out how to make a known standard, this will be an easy solve. I'm struggling with that part though. Chemistry is not my strong point.

 

[jsker]

It also sounds like you may be suggesting the Hanna may be more suspect of giving wrong results.
Or am I reading to far between the lines there?

Hanna will give a more accurate result if one uses clean testing tips and syringes. I really need to finish and edit videos on how I test. This was requested months ago by @William Morris

If I can figure out how to make a known standard, this will be an easy solve. I'm struggling with that part though. Chemistry is not my strong point.

Let me get to work and finishes the videos and I will post one here later or tomorrow so you can see what I am doing.

 

[JAC-]

Thanks friends,
I found just what I needed

DIY alkalinity standard

For folks who may want to evaluate the accuracy of their alkalinity test kits, here are two suggested ways to do it. One is DIY and one is a mostly commercial standard with one DIY step. Method 1 Standard solutions could be made with sodium bicarbonate, but it can be hard to be sure it hasn't...

www.reef2reef.com

I knew something had to be buried in he forms somewhere.
I'll let you know how it goes.

 

[jsker]

Thanks friends,
I found just what I needed

DIY alkalinity standard

For folks who may want to evaluate the accuracy of their alkalinity test kits, here are two suggested ways to do it. One is DIY and one is a mostly commercial standard with one DIY step. Method 1 Standard solutions could be made with sodium bicarbonate, but it can be hard to be sure it hasn't...

www.reef2reef.com

I knew something had to be buried in he forms somewhere.
I'll let you know how it goes.

Yes, Randy has some good information.

 

[JAC-]

Hanna will give a more accurate result if one uses clean testing tips and syringes. I really need to finish and edit videos on how I test. This was requested months ago by @William Morris


Let me get to work and finishes the videos and I will post one here later or tomorrow so you can see what I am doing.

That will be awesome @jsker Thanks.

 

[jsker]

That will be awesome @jsker Thanks.

And here you go, relearning adobe premier ;Hilarious

 

[JAC-]

And here you go, relearning adobe premier ;Hilarious

Awesome, I didn't hear any audio if there was any, but that could be on my end.
I'm going to look into getting some of that gear. Thank you greatly friend.

 

[JAC-]

ok. I'm throwing in the towel, at least for today and going to celebrate Independence day. Happy and safe Independence Day to those whom it applies.

Made the standard solution, tested three times with both kits.
Redsea results. 4.5, 4.3, 4.5 DKH
Hanna results. 4.9, 4.9,4.8 DKH

So there both reading about the same against the standard. The problem is the stock should have read 8 DKH

went back and tested my tank,
Redsea 8.6 DKH
Hanna 10.4 DKH

Guessing something in my tank is giving false alk readings on on of the kits, false high or low I do not know and I'm assuming I did something to make the stock ~ 50% less potent than it should have been.

Friends I wish you all the best