Is it safe to trust our test kits?

[StewL6]

I actually have an adjustable 1-10ml pipettor. Bought it for taking water samples for tests, but hardly ever use it. It's sort of large and I am lazy to take it out of its own box. Those 10ml syringes are much smaller and I store them in Hanna's boxes and I tend to use these instead. But I never got the Calcium test, I was reading rather negative reviews on it and wasn't even considering buying it. I was thinking of choosing one larger box for all Hanna photometers and their stuff, and when I get at that I will probably make room for the pipettor to fit in there as wellas well. I have the Phosphate and Alkalinity so far, was planning on get the Nitrate HR and probably a salinity (conductivity) meter.

It is tempting to buy the Calcium meter too, although the reagents for it are the most expensive for some reason. Do you say that negative reports on this checker are mostly because of inaccurate doses of reagents added during the test?

I actually believe that the tests that normally are carried out by titration should be carried out just that way rather than by color change when a known amount of reagent is added. I would rather use an automatic titrator but that falls in a different price range, unless I DIY one... And, I was surprised that Hanna's alkalinity tester actually works quite well. Anyone knows what's in that reagent they are using? I wish I could make a DIY replacement for it.

Yes on the Hanna calcium test was very hard and inconsistent to draw 100 micro liters or .10 ml with the syringe I would get very large range test results. I get very consistent results with the pipettor test to test. Hanna even includes one now I think with the calcium checker. But I like using my own. I even built a little storage rack for them on my test station area of my work bench. I am very confident of the Hanna checkers and reading this thread has given me an idea on pre checking my Alk regeant as I usually buy 6 to 10 regents at a time.

 

[Rmckoy]

I have noticed a few things …
1) your alk checker is in dkh and not ppm .

2) if you don’t shake the bottle of reagent prior to every test the last half of the bottle will always give lower ppm reading .
I have had bottles give numbers so far off I double checked with salifert to see if the extremely low number was true .

perhaps this is the reason behind some corals not looking happy .
If there was a better test kit for alk , I would consider switching and not trusting hanna

 

[Rjmul]

Couple things here. Do I trust my test kits? No not really.


what I've been doing with Hanna is when I use the last of a bottle I immediately test again with a new bottle.

regardless, 2 dkh is a a lot. I've never seen that level of discrepancy

 

[rowdyreefing]

Not from the pics of the test I see but I could be wrong. If its 2 then thats not acceptable.
Been using the same egg for 5+ years and always verify with salifert and elos. I test alk every morning on both systems and for whatever reason the Hanna now reads 0.5 higher.

Read the post. It is 2dkh. The checkers are proving that the reagent is off. The discrepancy is not between the checkers, the discrepancy is between the two photos.

 

[X-37B]

Read the post. It is 2dkh. The checkers are proving that the reagent is off. The discrepancy is not between the checkers, the discrepancy is between the two photos.

Wow. I read the post sorry.
I would send email or talk to Hanna as that much difference is horrible.
Im suprised Hanna has not chimed in as these posts get alot of exposure.
Again for what its worth all my reagents over the last 6 months have read high at 0.5-0.7.
I personally am going to Salifert and Elos backup now but will use up my last 2 as I just bought them and again 0.5 higher.
Hanna 7.5
Salifert 7.0
Elos 7.0
I am making the Randy alk standard and will check all within a week.

On a lighter note I have a 2.5 year old Salifert test kit im using. Your post made me buy a new one yesterday and it reads exactly the same as the 2.5 year old one.

 

[Littlemikey]

I recently had a regeant that came with my tester new in box test around normal levels and dosed accordingly. Color me shocked when I ordered a new regeant and it read 20DKH and the prior read 8.3.

 

[Littlemikey]

This past month I had bought a new Hannah alk. I used the kit at least weekly and dosed accordingly to maintain main stability. As I began to run low on regent I ordered a new one. I tested and it read 20DKH so using the same source water I did with new regent I used the old regent that I had left.

I was shocked to find out it read 8.3dkh. I confirmed with a salifert kit that indeed it was above max the salifert kit reads and explained why my coral were vacating their skeletons

 

[Tonyreeffish]

So I ran into an issue with the hannah alk checker and decided to post my thoughts here. Recently my alk numbers started dropping so i started dosing accordingly. Numbers keep dropping so I do a water change and now its down to 6.7.

I kept dosing trying to increase my alk gradually day by day but the number kept going down. I ordered new reagent and used it and my alk was 11.4 dkh. 11.4 and 6.7 are crazy different numbers.

I have since got the alk back to reasonable stable amounts and have conclude that as i got closer to the end of the bottle it just threw the number off further and further. Anyone else have this issue? Pretty drastic difference in readings. Luckily i didnt kill my corals off.

So my question is are you supposed to shake the reagent bottle to mix it up before use? I never did before and always had good readings. Could have just been the batch. I dont know. Another thing to point out is the reagent didnt expire for another year. Does the shelf life decrease once you open it?

I appreciate any thoughts on this situation. Thanks.

 

[vahegan]

So my question is are you supposed to shake the reagent bottle to mix it up before use? I never did before and always had good readings. Could have just been the batch. I dont know. Another thing to point out is the reagent didnt expire for another year. Does the shelf life decrease once you open it?

I think that was the conclusion of the community. After reading these reports, I have started shaking the reagent before every measurement. I started doing this when the bottle was already half-empty. There is very little left in it now. When I start a new bottle, I will report back if there was any significant difference in readings when I start the new reagent bottle.

 

[vahegan]

Unfortunately I didn't test the same water with the last portion of the old reagent and the new reagent. But my previous test on 17th read 9.4KH with the old reagent (which I was shaking before each use) and I measured 11.5KH today. There is no way that my alkalinity would increase by almost 2KH in less than a week (unless there was a crash in the tank and corals stopped growing - which did not happen). So, I am assuming that shaking the bottle is not sufficient to be able to get consistent KH readings after opening Hanna's KH reagent bottle. I am now going to try Lasse's method of storing the reagent in the fridge after opening. I will report back again when my bottle is finished and I open a new bottle, but it will take a while as I have just opened the new bottle and I usually test once a week.