Phosphate Testing

[therealfatman]

Hach now claims the only method of testing Phosphate at levels below 0.02 mg/L (ppm) is through the use of a flow through cell in my spectrophotometer. They have alterred their reagents specifications that used to say zero to 2.5 mg/L or zero to 30 mg/L to 0.02 to x.xx mg/L. Is this more a reresult of the possible errors or due to there being a very small amount of phosphate in their reagents. They claim an accuraccy of 0.01 + or -. Methods set forth for testing are universal standards. I do not understand why Hanna and Hach make different claims for the same method of testing.

Does anyone have an opinion on this?

 

[Billybeau1]

Boomer has strong opinions about this. He'll be along a little later I hope.

If I see him, I'll send him your way.

 

[therealfatman]

I realise that there is really no such thing as a test for a zero level of phoshate, and that Hach should never have listed their reagents as they did in the past. Hanna still lists their low range test as being for zero to 2.5 mg/L.

However I stil would like to know about readings in the 0.01 to 0.03 range from ascorbic acid method and amino acid method testing ie: methods 8178 and 8048. Do I really need to switch to a flow through cell method of testing to have somewhat reliable results for tests in the 0.01 to 0.03 mg/L range. I really do not see myself as having a need for readings in the micro range, and I do not ever anticipate doing enough phosphate tests to justify the increased reagent costs due to reagent ageing.

Then there is the almost $300 cost for the flow through cell, plus more glass ware. pipettes etc. Then again, just an optically matched pairs of 10ml or 25 ml cells at Hach cost around $125.

Photometer use is nice, but the initial investment is pretty steep. But ISE electrodes, reference electrodes and there arious fluids are not cheap either.

Ignorance might not be bliss, but it is obviously a cheaper way to live life in a lot of respects.

 

[Billybeau1]

<a href=showthread.php?s=&postid=13871265#post13871265 target=_blank>Originally posted</a> by therealfatman
Ignorance might not be bliss, but it is obviously a cheaper way to live life in a lot of respects.

Only if one chooses it to be.

 

[Boomer]

You lost me. Where is a link to that and what HACH unit are you talking about. When you say HACH and Hanna I take it as in the HACH Phosphate, Pocket Colorimeter II, which is a spectrophometer. And the same for Hanna. HACH is the top of the line stuff where Hanna is bottom self cheap stuff made in China.

The HACH website on the pocket unit still uses the same reagents..

The pocket specs have not change in years. Really old meter like int he 90's yes

Website
PhosVer® 3 Ascorbic Acid, Method 8048

http://www.hach.com/hc/search.produ...el=Phosphate,+Pocket+Colorimeter+II+Test+Kit/

Range = 0.02 to 3.00 mg/L PO43-

EDL = 0.02 mg/L PO43-

Same as my 2006 catalog and not 0 -3.00

http://www.hach.com/hc/search.produ...+mL+sample%2C+pk%26frasl%3B100+Powder+Pillows

Where is there a 8178 method for that meter ?

These are the methods, all AA, for that meter

http://www.hach.com/hc/view.parameter.range.reagent.info/2508025/

 

[Boomer]

Ok new post I see. Still what meter ? I take it is an old DR.

Crap my links don't work but so what :lol: Ok, I fixed then finally

HACH uses the Amino Method for high range. HACH has no low range for Amino. Where is this LR Amino Method down to 0.01 or even the Adsorbic Acid down to 0.01

Method 8178 = 0.23 to 30.00 mg/L PO43-

HACH methods for P

http://www.hach.com/hc/view.parameter.range.reagent.info/DR5000-01/JNVms1VldBPT1CVEV5TQ==

 

[Boomer]

I forgot , who cares if a meter is 0.01 or 0.02. I doubt in real expensive tests like ICP they would be that accurate. More like + or - 0.02 for these spectro's. I see now HACH at 0.01 The only meter I have seen that claims 0 - 3.00 ppm and MDL of 0.01 ppm is the LaMotte Smart Colorimeter/Spectrophometer

OOP's missed it. From that P link it is now only

PhosVer® 3, Method 8048 0.06 - 5.00 mg/L for the DR-5000 or any of pricey ones. The larger so called larger pricier colorimeter are

0.00 to 3.50 mg/L PO43- EDL 0.07 mg/L

 

[therealfatman]

It is an old DR/2010. The run down on the test are in the Procedues manual which is a downloadedable pdf file aof all theire tests (Hachs).

The low range Phosphate, (ortho phosphate) Amino Acid test 8178 is on page 663 and lists the test as zero to 30 mg/L. The Ascorbic Acid Phos Ver 3 test (8048) is on page page 667 and is listed as zero to 2.5 mg/L.

The extremely low range test requiring a flow thtough cell is 19 ppb to 3000 ppb and is test number 10055. It is listed as a Phosphorous, Reactive, low Range zero to 3 ppb. It is on page 685.

All the reagents are available through Hach online, as is the flow through cell.

I do not own a colorimeter. I would like a Hach DR/890 Colorimeter if you see a good used one on sell for a reasonable price. The last one on ebay was a usd one and it still sold for over $700.

The Procedures Manual is the most recent available one for the DR/2010. It was last revized in October 2000. Hach has did not tell me in the email they sent this morning when they changed to not staing the lower levels at zero.

Hach Low level Phos Ver 3 reagent link

http://www.hach.com/hc/search.produ...VOU1puZFdWemRFcFJSbE5QTVE9PUJqSXlPRE0wTg==%7C

The micro range test is at this Hach link:

http://www.hach.com/hc/view.file.de...RGsyTkRBMk1pWm5kV1Z6ZEVOSlMxaExNUT09QmpJeQ==|

If the links do not work just go to the Hach site and pump in the test number. The procedures Manual is also an]vailable as a free download. It is a 874 page PDF document.

 

[Boomer]

19 ppb to 3000 ppb

Well, that is only 0.019 ppm almost the same as 0.02 ppm

test as zero to 30 mg/L

But HACH does not give that level anymore

Method 8178 = 0.23 to 30.00 mg/L PO43-

I gave the link above


page 663 and lists the test as zero to 30 mg/L


Same here
667 and is listed as zero to 2.5 mg/L.

But it is

0 to 2.50 mg/L PO43- EDL =0.05 mg/L
Also posted above


It is listed as a Phosphorous, Reactive, low Range zero to 3 ppb. It is on page 685.

Where, it says...... 0 to 3,000 μg/L PO43-

There is not any 0 - 3 ppb, , that is 0.003 ppm

1 ppb = 1 ug / l

0 to 3,000 μg/L PO43- = 0 to 3,000 ppb PO43-

or = 0 - 3.00 ppm or mg / l is what that say above.

0 to 3,000 mg/L PO43- = 0 to 3,000 ppm PO43-

What I'm saying here is they are not making these claims anymore form what I have seen based on reagents now available.

. I would like a Hach DR/890 Colorimeter if you see a good used one on sell for a reasonable price. The last one on ebay was a usd one and it still sold for over $700.

I will I like to spend other peoples money :lol:

BUT IMHO and I'm sure Randy, these pricey toys are needed for hobby work or worth it.

 

[therealfatman]

I realise Hach is no longer making the claims to be able to test down to zero or near zero. I am curious about Hanna making claims to provide low range phosphate testing to zero ppm.

Also strange is the repetitive recommendations in forum threads to run levels of phosphate at as low as 0.01 ppm, when one of the top manafacturers of water testing equipment now claims to provide testing down to 0.02 ppm only. When people are claiming phosphate levels at 0.01 or below what tests are they basing these numbers on.

Hach states that the small amount of phosphate in the reagents does not allow for readings below 0.02 ppm except with the one method that will give readings as low as 0.019 ppm. Hach states that there will always be some blue coloration to the test sample after their reagents are added, therefore there is a reading of around 0.02 ppm as a minimum.

Boomer, I got a copy of Parson's A Manual of Chemical and Biological Methods for Sea Water Analysis from the University this morning to read this weekend. So far after just glancing through it appears to be a book a lot of reef keepers could benefit from. It at a glance looks like a book I would not mind owning. So far the cheapest price seems to be right at $90 plus shipping. Bummer, as that is for a book only 1/2 inch thick and 23 years old.

 

[Randy Holmes-Farley]

I am curious about Hanna making claims to provide low range phosphate testing to zero ppm.

Assuming that you mean the Hanna # 93713, then this Hanna specification page shows that while it says it has resolution of 0.01 ppm, it only has accuracy of +/- 0.04 ppm (click on the specification link when at that page)

http://www.hannainst.com/usa/prods2.cfm?ProdCode=HI 93713&id=009001001

 

[therealfatman]

Hanna might not be illegally misadvertising their product but their ethics seem to be a bit lacking. They claim a range of 0.00 to 2.50 mg/L, with a resolution of 0.01 mg/Land repeatable accuracy of 0.04 mg/L.

Hach claims a range of 0.02 to 2.5 mg/L, with a resolution of 0.01 mg/L and a standard deviation of 0.02 mg/L. Their written range claims seem to show a higher standard of ethics.

Now how are people coming up with all these readings of 0.01 ppm phosphate. This does not seem possible considering what Hach says about the reagents containing some phosphates.

 

[Boomer]

fatman

Parson's A Manual of Chemical and Biological Methods for Sea Water Analysis for the University this morning to read this weekend. So far just glancing through it seems to be a book a lot of reef keepers could benefit from. It at a glance looks like a book I would not mind owning. So far the cheapest price seems to be right at $90 plus shipping. Bummer, as that is for a book only 1/2 inch thick.

Yes, I agree on the book but the cost is NUTS. When I do my book searches once a week I'll try to keep you in mind for that book If nothing else fat's, time for the copy machine :lol: I once copied a $250 book about that size in thickness but bigger W/L on Zeolites. Many book prices make no sense at all.

When people are claiming phosphate levels at 0.01 or below what tests are they basing these numbers on.

Flat out they do not understand the meter and its sepec's and real issues. I think this is why HACH took the leap to fix and address this issue with their new ........

Method 8178 = 0.23 to 30.00 mg/L PO43-

Method 8048 = 0.06 - 5.00 mg/L

Range = 0.02 to 3.00 mg/L PO43-


No "0" there anymore.

What I was told by a tech 2 years ago, from Hanna, where say a meter is 0 - 100 ppm TDS and + or - 5 ppm TDS , that as the sample gets closer to zero it is not really + or - 5 ppm anymore but lower. Meaning, it could be + or - 1ppm. But they only guarantee the + or - 5 ppm. But that is a TDS meter and may not apply to others meters at all. Maybe Randy knows.

 

[therealfatman]

Boomer

I was thinking about scanning the book, but I really did not know how well that would go over on this forum. They are really tight at the University anymore about copy right infringements. We can not give out copies of any materials we use in class room presentations without specific written permission anymore if the come from a textbook. Even the instruction materials sent to us by publishers can not be copied by or distributed to students. When you consider what text books cost these days it makes one wonder who is retiring with all those funds.

 

[Boomer]

You are not giving out copies it is for yourself. One can quote from a books and give it ref., is common. This is also the internet.

I can go to my public library and tell them I want a peer-viewed article out of x, y or x journal. They will not even have it and will send a request to some U that has it and poof in 2 wks I have it at no cost at all.......FREE. But that is not a book

However, with all that said, things are tightenig up as you can see here when dealing with books.

http://books.google.com/googlebooks/agreement/

 

[therealfatman]

It will be interesting to see what the costs will be like. There are many out of print books I would love to own, and an unbound paper copy may be the closest I will ever come to owning some of the books. I wonder how long it will take fot this project to make much headway?

 

[Ralph ATL]

you could just use DD Merck and be done with it. I had a hach kit at the same time, and both read the exact same amount, everytime.

 

[therealfatman]

The Hach test is really simple and cheap, once you have the spectrophotometer. Like around $25 for 100 tests. Plus I am not that great at tests where I have to use my eyes to judge the color.