Is it safe to trust our test kits?

[rowdyreefing]

Hi Guys,

I understand that hobby grade test kits are used more for reference and stability. I also understand that number chasing isn't always the best to do with our reef tanks. But I would like to share a story (photos included) and get your input.

For years my hanna alk checker has been the bible. I would trust it over my apex trident. Within the last month, I noticed my checker started giving very high readings, so I decided it was for $50 to replace it. Upon arrival of the new checker, I got very high alk readings complimenting the older checker's readings. After trying multiple cuvette, syringes, etc I was able to narrow down that the two reagents, purchased 2 months apart, were about 2dkh different from each other. I was able to replicate the attached results multiple times indicating it was in-fact the reagents.

I understand there should be so tolerance in these test kits, but 2dkh seems to be a lot. What are your thoughts?

 

[blaxsun]

It doesn't seem - 2 dKH is a lot. In answer to your question: "Only as far as we can throw them". I wish I knew what to tell you. Quality control in our hobby has gone to absolute sh*te over the past few years...

 

[mdb_talon]

I have almost that same exact story i been trying to share here(though i had three reagent batch #s i tried with). Most people just want to hear that hanna is the gold standard because it is digital. Its only as good as the QC of the regeants though. In my case i could repeatedly get same results with the same regeant batch ids, but wildly different results with different batch(though again repeatable within that batch. To me that ruled out user error, curvette issues, etc.

I do agree i dont expect perfection and there is a margin of error. Over a 2dkh swing though between regeant bottles is unreasonable. I use salifert and nyos for my alk readings now.

 

[rowdyreefing]

I have almost that same exact story i been trying to share here(though i had three reagent batch #s i tried with). Most people just want to hear that hanna is the gold standard because it is digital. Its only as good as the QC of the regeants though. In my case i could repeatedly get same results with the same regeant batch ids, but wildly different results with different batch(though again repeatable within that batch. To me that ruled out user error, curvette issues, etc.

I do agree i dont expect perfection and there is a margin of error. Over a 2dkh swing though between regeant bottles is unreasonable. I use salifert and nyos for my alk readings now.

This is a bummer. I use to be someone that though hanna is the gold standard. I may go back to my salifert, because the trident worries me as well.

 

[rowdyreefing]

It doesn't seem - 2 dKH is a lot. In answer to your question: "Only as far as we can throw them". I wish I knew what to tell you. Quality control in our hobby has gone to absolute sh*te over the past few years...

I am starting to realize this...

 

[blaxsun]

This is a bummer. I use to be someone that though hanna is the gold standard. I may go back to my salifert, because the trident worries me as well.

I still use my Nyos test kits for nitrate and phosphate. At some point when my Hanna testers run out of reagent I'll probably switch to Nyos for alkalinity and calcium as well.

 

[sublime275]

i haven’t had the problem you are having, but I always have backup test kits of different brands to verify each other.

 

[rowdyreefing]

I still use my Nyos test kits for nitrate and phosphate. At some point when my Hanna testers run out of reagent I'll probably switch to Nyos for alkalinity and calcium as well.

I haven't tried the nyos before. I will get them in my test suitcase! haha

 

[homer1475]

Question I have is, how many test did you perform out of the old bottle?

I have noticed that as the bottle gets old, and you go past the stated 25 tests, thats when variations start to occur between reagent bottles.

I started marking my bottles for only 25 tests. If I continue to use the old bottle past 25 test(there is 30ml of reagent in the bottle), the reading start to go higher. If I throw it out after 25 tests and open a new, I get the same results batch to batch.

 

[SDK]

Test kit usage comes down to common sense and the maxim of "trust but verify"...

As I switched to Hanna testers I verified results against the high quality Red Sea kits I was replacing them with. So far, all have been pretty dead on. I still keep the RS kits in case I want to verify a testing anomaly. Buying another liquid kit if the need arises, or getting a comparative test at the LFS are also viable options for just about anyone.

Test often enough that you will notice drastic or unusual changes. Use one of the above methods to verify the results, then fix the test kit or the problem in the tank, depending on which one it was..

To the OP- Good on you for basically doing what you did and tracking the problem down.

At the end of the day, these are the tools we have to work with. They have improved greatly over the years, but you still need to keep your brain active and your eyes closely monitoring your tank...

 

[Dilan Patel]

I believe once opened the bottle must be used within 30 days of opening or 25-30 tests. The amount of opening and closing of the bottle must allow either one of the reagents they use to evaporate or oxidize slightly skewing the results. I had the same issue. not sure if this would work but you may go find yourself a glass vial big enough to hold all the liquid when you first open it and get a cap with a self-healing septum. This would mean less opening and closing of the cap But you would have to use the proper gauge needle to extract the reagent.

 

[Daniel@R2R]

A few things I do:
1) Have some kind of verification system with a separate test kit. If your readings seem off with one, check it with the other.
2) I test for stability more than I do a specific number. If my readings are consistent and in range, and everything looks OK, I'm not going to stress.
3) I expect one batch of reagent may at times vary from others. In those cases, I go back to rule #2 here. I'm not happy about variance, but I know it does happen occasionally. I think most manufacturers would be willing to replace a defective reagent batch if contacted.

 

[MONTANTK]

Very interesting. I may go out and buy a Salifert Alk kit to compare it against my Hanna. I’ve been using Red Sea for nitrate and phosphate and I have no complaints. I use salifert for calcium and magnesium. Every once in a while I might get a weird magnesium result but generally speaking the kits are consistent

 

[Sherman]

So far not such problem since I start Hanna PO4 5 years ago.
I verify it every 3 months with ICP test

 

[rowdyreefing]

Question I have is, how many test did you perform out of the old bottle?

I have noticed that as the bottle gets old, and you go past the stated 25 tests, thats when variations start to occur between reagent bottles.

I started marking my bottles for only 25 tests. If I continue to use the old bottle past 25 test(there is 30ml of reagent in the bottle), the reading start to go higher. If I throw it out after 25 tests and open a new, I get the same results batch to batch.

The bottle was problematic on the very first test when opening!

 

[jgirardnrg]

I had an Alk tester go out of calibration and one of the steps when dealing with support was to give them the batch number from the bottle. Apparently when the reagent starts to turn it start getting yellowish. Whether this is from contamination, bad batches, age etc I don't know. I bought the standard prior to contacting them and my tester was out of range. I sent photos and the like to the guy I was dealing with and he called me straight away and by the time we got off the phone I had an order email for a new tester headed my way. I did have to send the old one back to them on my dime but it was only a few bucks to slap a label on the box and send it back Priority Mail. When I received the new unit I opened 2 new bottles of reagent from different batches and tested my water. They were within .1 of each other. I also tested the unit with the standard and it was where it should be. I keep backup Red Sea pro and Salifert tests and run those instead of the Hanna every 10th test or so to make sure everything is as it should be in case one of the Hanna's acts up again.

 

[X-37B]

From what I see its 0.2dkh not 2. That is well within tolerance, imo.
I have a egg that reads almost 0.5dkh higher than my salifert and elos. It started about 3-4 months ago. I have changed batterys and vials but it still 0.5dkh higher.
I always have 2 ways to measure everything and 3 for alk as its the most important, imo.

 

[rowdyreefing]

From what I see its 0.2dkh not 2. That is well within tolerance, imo.
I have a egg that reads almost 0.5dkh higher than my salifert and elos. It started about 3-4 months ago. I have changed batterys and vials but it still 0.5dkh higher.
I always have 2 ways to measure everything and 3 for alk as its the most important, imo.

It is 2dkh. Not 0.2 dkh.

 

[X-37B]

It is 2dkh. Not 0.2 dkh.

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.

 

[X-37B]

Randy has a test standard you can make. Reviewing this thread I remembered it, lol.
I have never tried it but am going to do so now and then test Hanna, Salifert, and Elos so I can have faith again.