Dennis Cartier
Valuable Member
- Joined
- Aug 25, 2016
- Messages
- 1,970
- Reaction score
- 2,409
- Location
- Brampton, Ontario
- What state or country do you live in
- Canada
The last box of Hanna reagents for my HI736 had a couple of envelopes that produced bad tests. There were at least 2 reagents where the vial turned dark blue. The one test was over the limits of the tester. when it happened, my immediate reaction was "What is going on?". My PO4 is normally around 0.10 -0.15, so to suddenly be above 0.61 was surprising. After it happened once, I was looking for the problem with my tank. When the next bad test occurred, which was the next day, and it went over the limit of the tester, the light in my head went off. It's not my water, it's the tester. A quick Salifert test confirmed my suspicions. The reagents were bad.
Fast forward to today, I opened a new box yesterday and my water tested at 0.12. Ok, that seems reasonable. I fed 1 cube of VH Marine Fusion last night and tested just now. Vial turned dark blue and the tester showed over the limit (>0.61). So I ran a second test on the same water, using a new reagent and got 0.16. That seems more in line with what I was expecting, but it brings up a larger question. If the reagents can return so incorrect results as to being over the limit, and then the next reagent returns a much lower result, how can any of them be trusted?
I did a Salifert test as well. The colour was greater than 0.10 but less than 0.25. Which is why I would prefer to use the digital tester as it "should" produce a finite answer.
This is all very frustrating. Sure I can contact Hanna and they will replace the $15 box of reagents, but the lack of a dependable way of getting consistent results makes addressing water column problems very hard.
Sigh, I am off to dose enough LaCl to bring my PO4 below 0.1 ... which may or may not be needed.
Dennis
Fast forward to today, I opened a new box yesterday and my water tested at 0.12. Ok, that seems reasonable. I fed 1 cube of VH Marine Fusion last night and tested just now. Vial turned dark blue and the tester showed over the limit (>0.61). So I ran a second test on the same water, using a new reagent and got 0.16. That seems more in line with what I was expecting, but it brings up a larger question. If the reagents can return so incorrect results as to being over the limit, and then the next reagent returns a much lower result, how can any of them be trusted?
I did a Salifert test as well. The colour was greater than 0.10 but less than 0.25. Which is why I would prefer to use the digital tester as it "should" produce a finite answer.
This is all very frustrating. Sure I can contact Hanna and they will replace the $15 box of reagents, but the lack of a dependable way of getting consistent results makes addressing water column problems very hard.
Sigh, I am off to dose enough LaCl to bring my PO4 below 0.1 ... which may or may not be needed.
Dennis
