Boga
Active Member
- Joined
- Jan 12, 2012
- Location
- Dorchester, Ontario
I want to make it clear from the beginning. This review is not for the Hanna Checker Phosphorus ULR. It is for the reagent HI 736-25 Lot # H025. It is only for lot 25.
This review is not against any of the dealers that carry Hanna's products. My review is not to boycott Hanna or its dealers. It is to make reefers and dealers aware about this possible defective lot #25.
I purchased this Checker HI736 Phosphorous ULR because I've read good reviews on this forum and many other sites. I also bought a pack of 25 tests HI 736-25, lot # H025, expiring date 02/2016.
I performed multiple tests and nothing made sense. Results were scattered all over. I even tested RODI water (zero TDS) and found high phosphates. I searched on internet and I realized that I am not alone. Many people reported issues with this lot and some forums show that even Hanna (at one point) acknowledged this type of issues. The latest is that "not all the reagents in lot 25 are defective". Some of them are bad, some of them are not.
I wrote to Hanna USA and the tech rep said that "I have not had any complaints on this lot". They directed me to Hanna Instruments Canada. No comments from Hanna Canada, yet. But they were nice and they sent me a new lot at no cost. I received lot # H035, expiring date 07/2016.
Today I did a comparison test between lots H025 and H035. Testing procedure and results are shown down below. You can see that lot 25 is reading higher, consistent with test results from other reefers and Hanna USA. It also show that the results are not consistent, going out of the instrument's accuracy.
1. I used only one vial for all tests. All tests were performed back to back.
2. Collected one glass of saltwater from my sump. All tests were performed from this sample.
3. Clean vial with tap water.
4. Rinse vial in RODI water (zero TDS) for about 15 seconds.
5. Add 10 mL of saltwater.
6. Run tests per Hanna's instructions. All tests were in C2 aprox 2 minutes and 45 seconds
7. Back to point 3 and perform the next test.
Resolution of the instrument is 1 ppb.
Accuracy is +/- 5 ppb.
Phosphorous [ppb]
Lot# H025 Lot# H035
Test 1 | 32 ppb | 0 ppb
Test 2 | 11 ppb | 5 ppb
Test 3 | 27 ppb | 1 ppb
For conversion to Phosphates I used the following formula:
ppt = ppb * 3.066/1000
Phosphates [ppt]
Lot# H025 Lot# H035
Test 1 | 0.098 ppt | 0 ppt
Test 2 | 0.034 ppt | 0.015 ppt
Test 3 | 0.083 ppt | 0.003 ppt
As a conclusion I think that the Phosphorous ULR checker is a good instrument, accurate for reading a low level of phosphorous (phosphates) in marine systems, but stay away from reagent LOT H025. Also I will salute if a new way of adding the reagent into the cuvette is going to be developed by Hanna.
Few references from internet. You can Google "Hanna defective lot 25". More will show up.
http://www.nano-reef.com/topic/333784-problems-with-hanna-phosphate-and-phosphorus-checkers/page-3
http://www.zeovit.com/forums/showthread.php?p=284244
This review is not against any of the dealers that carry Hanna's products. My review is not to boycott Hanna or its dealers. It is to make reefers and dealers aware about this possible defective lot #25.
I purchased this Checker HI736 Phosphorous ULR because I've read good reviews on this forum and many other sites. I also bought a pack of 25 tests HI 736-25, lot # H025, expiring date 02/2016.
I performed multiple tests and nothing made sense. Results were scattered all over. I even tested RODI water (zero TDS) and found high phosphates. I searched on internet and I realized that I am not alone. Many people reported issues with this lot and some forums show that even Hanna (at one point) acknowledged this type of issues. The latest is that "not all the reagents in lot 25 are defective". Some of them are bad, some of them are not.
I wrote to Hanna USA and the tech rep said that "I have not had any complaints on this lot". They directed me to Hanna Instruments Canada. No comments from Hanna Canada, yet. But they were nice and they sent me a new lot at no cost. I received lot # H035, expiring date 07/2016.
Today I did a comparison test between lots H025 and H035. Testing procedure and results are shown down below. You can see that lot 25 is reading higher, consistent with test results from other reefers and Hanna USA. It also show that the results are not consistent, going out of the instrument's accuracy.
1. I used only one vial for all tests. All tests were performed back to back.
2. Collected one glass of saltwater from my sump. All tests were performed from this sample.
3. Clean vial with tap water.
4. Rinse vial in RODI water (zero TDS) for about 15 seconds.
5. Add 10 mL of saltwater.
6. Run tests per Hanna's instructions. All tests were in C2 aprox 2 minutes and 45 seconds
7. Back to point 3 and perform the next test.
Resolution of the instrument is 1 ppb.
Accuracy is +/- 5 ppb.
Phosphorous [ppb]
Lot# H025 Lot# H035
Test 1 | 32 ppb | 0 ppb
Test 2 | 11 ppb | 5 ppb
Test 3 | 27 ppb | 1 ppb
For conversion to Phosphates I used the following formula:
ppt = ppb * 3.066/1000
Phosphates [ppt]
Lot# H025 Lot# H035
Test 1 | 0.098 ppt | 0 ppt
Test 2 | 0.034 ppt | 0.015 ppt
Test 3 | 0.083 ppt | 0.003 ppt
As a conclusion I think that the Phosphorous ULR checker is a good instrument, accurate for reading a low level of phosphorous (phosphates) in marine systems, but stay away from reagent LOT H025. Also I will salute if a new way of adding the reagent into the cuvette is going to be developed by Hanna.
Few references from internet. You can Google "Hanna defective lot 25". More will show up.
http://www.nano-reef.com/topic/333784-problems-with-hanna-phosphate-and-phosphorus-checkers/page-3
http://www.zeovit.com/forums/showthread.php?p=284244
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