shaywood Posted February 26 Share Posted February 26 I've had the same Hanna checker for approx 7 years. On the 18th I completed a test with a result of .13. On the same day I sent in an ICP test, which showed .03. Is there a shelf life the Hanna checkers, or are they accurate as long as we use non-expired reagent? Shawn Quote Link to comment Share on other sites More sharing options...
Lexinverts Posted February 26 Share Posted February 26 The vials can get worn out. Lots of scratches on the vials can make readings be too high. I would not worry about the unit itself though. I have not heard of that going bad. Quote Link to comment Share on other sites More sharing options...
steveweast Posted February 26 Share Posted February 26 How about bacterial processes affecting the results? Hanna results are instantaneous but ICP takes days, weeks or even a month. Could bacteria within the sample over the long shipping time diminish the PO4 results? I know that that all my ICP test results show lower than Hanna too. Quote Link to comment Share on other sites More sharing options...
cjmdh Posted February 26 Share Posted February 26 You can get the standards to test the accuracy of the checker. As long as you keep them stored in their protective light proof box and don't scratch them up they should be good for quite a while. Quote Link to comment Share on other sites More sharing options...
shaywood Posted February 26 Author Share Posted February 26 What do you mean by, You can get the standards to test the accuracy of the checker. " Quote Link to comment Share on other sites More sharing options...
Krux Posted February 26 Share Posted February 26 These bad boys, they make them for each checker, just make sure you get the right one for the checker you are using 2 Quote Link to comment Share on other sites More sharing options...
cjmdh Posted February 26 Share Posted February 26 Yeah what he said. ⏫ Quote Link to comment Share on other sites More sharing options...
obrien.david.j Posted February 26 Share Posted February 26 Thanks for the reminder. Just got mine ordered. I use H736. Added it to an order of BenePets I needed. HI736-11 Phosphorus Calibration Check Set for HI736 Checker - Hanna Instruments 160g BeneReef Reef Food - BenePets Quote Link to comment Share on other sites More sharing options...
Krux Posted February 26 Share Posted February 26 28 minutes ago, obrien.david.j said: Thanks for the reminder. Just got mine ordered. I use H736. Added it to an order of BenePets I needed. HI736-11 Phosphorus Calibration Check Set for HI736 Checker - Hanna Instruments 160g BeneReef Reef Food - BenePets Yep, gotta get the correct one - I order the wrong reagents half the time and now have like 500 tests for the other checker that have gone out of date... Quote Link to comment Share on other sites More sharing options...
shaywood Posted February 26 Author Share Posted February 26 What do you do if the calibration fluid shows the testers incorrect? Quote Link to comment Share on other sites More sharing options...
obrien.david.j Posted February 26 Share Posted February 26 1 hour ago, Krux said: Yep, gotta get the correct one - I order the wrong reagents half the time and now have like 500 tests for the other checker that have gone out of date... I keep a list of my three testers I've used regularly. So I can always spot check the exact number when ordering. My main three Hanna tests are: HI736, HI782, HI705 (silica, when I'm dosing it) 46 minutes ago, shaywood said: What do you do if the calibration fluid shows the testers incorrect? I'll at least know it's off, and in what direction. I'm not a stickler for perfect numbers. I'm more of a directional trend person. (and I use ICP often enough, if I'm SUPER off, it can help me know that) 1 Quote Link to comment Share on other sites More sharing options...
Krux Posted February 26 Share Posted February 26 1 hour ago, shaywood said: What do you do if the calibration fluid shows the testers incorrect? Personally I would note the +/- in sharpie on the back of the checker and then manually make that change whenever i run a test. I don't trust myself to remember those variations. Quote Link to comment Share on other sites More sharing options...
Krux Posted March 3 Share Posted March 3 The Hanna booth rep said today that unless you can see physical damage or scuffing on the cuvette there isn’t a recommended replacement schedule. 2 Quote Link to comment Share on other sites More sharing options...
obrien.david.j Posted March 3 Share Posted March 3 On 2/26/2024 at 9:29 AM, obrien.david.j said: Thanks for the reminder. Just got mine ordered. I use HI736. Bit disappointed. My HI736 calibration check kit came in, ran it yesterday. Cal kit itself is for 100 +/- 10. That's Phosphate of 0.307 +/- 0.031. In general, I've been trying to keep phosphate in the 0.06-0.09 range. So the error alone on the cal solution is near the range I'm targeting. BTW, my checker was within cal solution range. Nothing wacky off. If anyone wants to check their HI736, cal set is easy to borrow - or just bring your tester (no vials needed) to the next club meeting, at Brittany's place in Tillamook, and I'll bring the cal set along. You can check your tester on the spot. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.