Reef Jeff
Active Member
- Joined
- Dec 27, 2017
- Messages
- 214
- Reaction score
- 220
- Location
- NorthCentral PA
- What state or country do you live in
- Pennsylvania
I primarily use Red Sea test kits, but I’ve been curious about the Hanna ULR Phosphate egg because the device reads the test results for you. Randy recently commented to me in another post about confidence in your test kits. I was curious so I bought the Hanna ULR and ran a comparison: Red Sea Phosphate showed .08 ppm. The Hanna ULR read 20 ppb which is .02 ppm. A friend of mine also has a Red Sea test kit so we then ran the same tank water using his to rule out bad reagents and still got .07 - .08 ppm. Repeated tests with the Hanna ranged from 18 ppb to 22 ppb (.018 - .022 ppm) on subsequent tests. Both kits were repeatable within their stated range of accuracy.
We then ran the Red Sea test on fresh mixed salt water and got .02 ppm so we know the test detects different levels. That same fresh salt water tested with Hanna at 3 ppb which is .003 ppm.
I’m sure some of you have tried this same comparison. I realize these are hobby test kits and there is broad margin of error, but this is a significant difference. If one was to take action, the Red Sea kit would suggest the need to increase export with chaeto, GFO, Carbon dosing, etc., but if one took action based on the Hanna test result you might leave it alone or try to export less by taking GFO off line, reduce carbon dosing, feed more etc. My main point is the wrong intervention can cause trouble.
Just curious what others do with this conflicting information? Truth is I can answer my own question: my main concern is to stay above zero and below .1 ppm. The good news is, I’m in that wide ballpark, but I still find the variance disturbing. Guess I’m disappointed in the faith I put in Red Sea. My tank seems to do best at .08 - .1 ppm on Red Sea test, which apparently is .02 - .03 on Hanna. It would be nice If I knew which level is real? This certainly explains why some of us disagree on a “good” PO4 level.
Interested in hearing other opinions!
We then ran the Red Sea test on fresh mixed salt water and got .02 ppm so we know the test detects different levels. That same fresh salt water tested with Hanna at 3 ppb which is .003 ppm.
I’m sure some of you have tried this same comparison. I realize these are hobby test kits and there is broad margin of error, but this is a significant difference. If one was to take action, the Red Sea kit would suggest the need to increase export with chaeto, GFO, Carbon dosing, etc., but if one took action based on the Hanna test result you might leave it alone or try to export less by taking GFO off line, reduce carbon dosing, feed more etc. My main point is the wrong intervention can cause trouble.
Just curious what others do with this conflicting information? Truth is I can answer my own question: my main concern is to stay above zero and below .1 ppm. The good news is, I’m in that wide ballpark, but I still find the variance disturbing. Guess I’m disappointed in the faith I put in Red Sea. My tank seems to do best at .08 - .1 ppm on Red Sea test, which apparently is .02 - .03 on Hanna. It would be nice If I knew which level is real? This certainly explains why some of us disagree on a “good” PO4 level.
Interested in hearing other opinions!
