Phosphate Discrepancy

[malx]

Alright, I need some advice here. I have checked my phosphates with 3 different Hanna phosphorous checkers and with 3 sets of regants all performing the test the same way, like a ritual, back to back. They all pull in the same result averaging around 0.25ppm of phosphates.

Triton ICP shows my phosphates at 0.04ppm.

This is a huge difference, I don't know who to believe. Of course Triton says that the 0.04 number is correct and Hanna is not, but the third test kit I used, the person who owned it runs the ATI ICP tests and he says it's 0.01 different.

This is obviously a huge discrepancy.

What do you guys think?

Thanks,
Joey

[mcgyvr]

What problems are you having besides getting stuck on numbers?

Wanna know whos right.. buy a phosphate standard/reference and test it with your test kits..

Does ICP testing only test for Orthophosphate or does it also test for Organophosphate? And same for Hanna..
I believe Hanna only measures inorganic phosphate and ICP can measure both.. This however should result in ICP testing higher than a Hanna kit..

[malx]

What problems are you having besides getting stuck on numbers?

Wanna know whos right.. buy a phosphate standard/reference and test it with your test kits..

Does ICP testing only test for Orthophosphate or does it also test for Organophosphate? And same for Hanna..
I believe Hanna only measures inorganic phosphate and ICP can measure both.. This however should result in ICP testing higher than a Hanna kit..

Something like this?
https://hannainst.com/hi736-11-phosphorus-checker-calibration-set.html

[malx]

What problems are you having besides getting stuck on numbers?

Wanna know whos right.. buy a phosphate standard/reference and test it with your test kits..

Does ICP testing only test for Orthophosphate or does it also test for Organophosphate? And same for Hanna..
I believe Hanna only measures inorganic phosphate and ICP can measure both.. This however should result in ICP testing higher than a Hanna kit..

I have corals that are browning out/STN.

[mcgyvr]

Something like this?
https://hannainst.com/hi736-11-phosphorus-checker-calibration-set.html

yes something like that.. but if I was concerned about the validity of one companies test kit I would NOT buy their reference..Get one from another company..

[malx]

yes something like that.. but if I was concerned about the validity of one companies test kit I would NOT buy their reference..Get one from another company..

I looked online but can't find anything. I'm not sure what else would with with that checker.

[hkgar]

You might want to take this to the Reef Chemistry forum. I am not a chemist, but the difference may be that the Hanna checks Phosphorus, then you convert it to a Phosphate number. and the others check Phosphate.

[thegrun]

The Hanna checker itself does a very good job at reading the true color and giving an accurate reading but the Hanna reagents themselves seem to leave a lot to be desired. I get fairly substantial differences in my test results frequently when I switch from one batch of reagents to another. It's a good practice to test your new box of reagents against the the old box when you get down to your last package, I've had several cases where the results were off by a significant amount. I wish Hanna would do a better job of publicizing when a batch lot is found to be bad. They do replace the bad reagents if you contact them, but I have never seen where they actively post faulty batches.

[mcgyvr]

The Hanna checker itself does a very good job at reading the true color and giving an accurate reading but the Hanna reagents themselves seem to leave a lot to be desired. I get fairly substantial differences in my test results frequently when I switch from one batch of reagents to another. It's a good practice to test your new box of reagents against the the old box when you get down to your last package, I've had several cases where the results were off by a significant amount. I wish Hanna would do a better job of publicizing when a batch lot is found to be bad. They do replace the bad reagents if you contact them, but I have never seen where they actively post faulty batches.

A bad batch should never make it out the door of their own facility..
Sounds like they have an inferior quality control procedure there..

I've always looked at the stated accuracy/precision results and thought that they are mostly BS in this hobby...
Its also why I usually recommend not chasing a number... You can't even rely on the numbers you get so how can you chase a perfect one..