SE Mich check your RO/DI for PO4

Something I found interesting:
Phosphate (PO4) and your RODI system - Reef Central Online Community

Thank you AZDesertRat

I decided to do a series of testing. I was concrete on my methodology so I decided to try another batch of reagent..well reading were even higher! As I then wanted to pull my hair out (what's left anyway). In complete frustration I tested every water sample from tap to tank! @ this point I am sure some know the one thing I did not do FIRST...sample distilled water to see if any PO4 value obtained
You see I failed a basic procedure of a meter (verifying its accuracy :( ) my Chem Prof would blow a gasket!

***important rule of thumb...if readings seem off then check w/ a reference!!!***

Hobbyists are asking a lot out of a small handheld, hobbyist grade tester. Phosphates are tough enough to test accurately with multi thousand dollar benchtop lab grade instruments much less a handheld and expect accuracy or repeatibilty in the ppb or ug/L range. I wish I still had it but back in my private water utility management days I had a colleague who did a talk at an AWWA convention using common measurements for real world comparisons. Things like a drop in a Boeing 747 fuel tank, or grains of sand in an olympic size swimming pool or such and it really made people realize what these levels mean. This was back when the EPA was first talking about Arsenic in drinking water and the 5 parts per billion MCL which was and still is ridiculous but that is a different story.

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Originally Posted by dknuckles

Thank you AZDesertRat

I decided to do a series of testing. I was concrete on my methodology so I decided to try another batch of reagent..well reading were even higher! As I then wanted to pull my hair out (what's left anyway). In complete frustration I tested every water sample from tap to tank! @ this point I am sure some know the one thing I did not do FIRST...sample distilled water to see if any PO4 value obtained
You see I failed a basic procedure of a meter (verifying its accuracy :( ) my Chem Prof would blow a gasket!

***important rule of thumb...if readings seem off then check w/ a reference!!!***

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I'm not sure I would even trust regular distilled water that was transported in a non-lab grade container. I recall theories about plastic containers leeching phosphates.

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Originally Posted by jimsflies

I'm not sure I would even trust regular distilled water that was transported in a non-lab grade container. I recall theories about plastic containers leeching phosphates.

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You are correct! I did a thread testing a few different items and the "Brute" trash can leached quit a bit as tank water storage. This is a standard milk jug the Dist Water was in.

New meter here tomorrow, cannot wait to see the #s[COLOR=

You should see if you can find a lab grade calibration fluid for phosphates.

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Originally Posted by jimsflies

You should see if you can find a lab grade calibration fluid for phosphates.

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Found 1 but it is $189! Not sure if a typo??
I'm going to send Dejavu a PM, last we talked he knew how to make a reference solution...then again that may be like me explaining how to crack a safe...$189 may be cheaper in the long run lololol

Update:

Recvd new meter, reagent replaced few weeks before and to no avail ro/di was reading .24! So (in haste) I decided to order the "cibration/reference cavettes" and aprox $150 shipped..and meter measures to specification :(

I decided to check another's tank to see if a different reading...I think you know the number???.24
So I silently scream in money flushing agony when I decided to contact Hanna
Hanna's tech support Pete was very helpful and believes reagent as well. I have to p/u reagent Thursday and have a friend come over w/ his checker and do a couple comparison contrast tests

****for those asking if reagent is same for Hanna checker vs. meter the answer is YES per Pete @ Hanna****
So all you meter guys can now buy a 25pk instead of 100 (keep um fresh!)

Oops......

Again, the phosphate checkers will never be accurate when testing ultrapure waters like RO/DI or distilled, you are asking too much from a hobbyist grade meter.