Problems with Hanna Phosphate and Phosphorus checkers

[ElmoC]

Either the procedure you are following is off or the reagents are bad. Even though the phosphate checker is listed as +/- 0.04 ppm, when tested against actual lab equipment, it is much, much more accurate. Their alkalinity test is definitely +/- 5ppm (consistently at least), but the phosphate one is much, much better. The Salifert Phosphate test simply isn't sensitive enough to differentiate between 0.00 and 0.06ppm accurately or repeatably.

 

I am following the directions exactly with the addition of making sure the vial is aligned identically between the C1 and C2 tests.

 

I am leaning towards bad reagents because the packages have no storage specifications. However, I found on the safety sheets that they need to be kept between 15 and 25 Celsius (59 - 77 Fahrenheit). I know there was a period during one of our hot spells they got over that temp. We'll see how new reagents work with consistency.

[jservedio]

I am following the directions exactly with the addition of making sure the vial is aligned identically between the C1 and C2 tests. I am leaning towards bad reagents because the packages have no storage specifications. However, I found on the safety sheets that they need to be kept between 15 and 25 Celsius (59 - 77 Fahrenheit). I know there was a period during one of our hot spells they got over that temp. We'll see how new reagents work with consistency.

 

Make sure you get the reagents from a reputable place too (like BRS, Marine Depot, a Lab Supply Company, etc.) instead of a LFS which may not have kept the reagents according to specification or let the expiration lapse. Based on what you are saying, I would tend toward bad reagents. E-mail Hanna and give them the lot number and expiration and they may replace the reagents for free. If you have the same problem after you get new reagents, talk to Hanna - they may offer to replace it or fix it or modify the procedure for you to account for some unknown.

 

When you get new reagents, keep them in a cool, dark place - I keep them in a drawer in my 2nd bathroom because my closet with all the fish stuff gets way too hot. Also, always make sure the meter doesn't move once it is turned on and that the lid is closed when you turn it on and that it stays correctly sealed throughout the test.

 

Another big thing to consider - what are you using to make sure you have exactly 10ml in the cuvette? I try to use a very accurate 5ml syringe (2 times) because the line that is on the cuvette isn't very fine. Also, you should be measuring from the meniscus (http://en.wikipedia.org/wiki/Meniscus). Measuing from the wrong spot or inconsistently will throw it way off - since you are measuring such tiny changes in only 10ml, the smallest mis-measurement will throw off the results. Also, how do you open the reagent pouch and get the reagent in the cuvette?

 

Note: With the Alkalinity test - you can't use the syringe they provided since it sucks and isn't consistent (I ended up using the Salifert syringes which are much better). Make sure the measurement line on your cuvette is accurate (use a secondary measuring device like a high-quality syringe or pipette). Some of the stuff they provide is garbage, but the colorimeter itself is really high quality. If you got a lemon - make sure you have them replace it for you.

[Apexdv]

Sorry in advance for this lengthy post but ... I agree with others regarding the reagent possibly being spoiled. As far as the reagent packet and mixing I always tap the packet a bit to settle it to the bottom, slice the top off with scissors, squeeze it gently to pop it open then tap each side to make sure the reagent powder is not tucked away in the corners. I then ready a timer for 1:45 (I use the microwave "kitchen timer").

 

After, I grab the cuvette and rinse several times in the tank water to be tested (I do this over the tank with a syringe) in order to make sure all RODI has been removed and to equalize the temperature of the glass a bit. Next, I pop on the lid then carefully clean the cuvette and *only* hold it by the lid. Before beginning the test I hold it up to the light to ensure no fingerprints, dust, etc are present then immediately turn on the phosphate checker, wait for the "C1" indicator then pop the lid, plop in the glass vial and hit the button.

 

Once the prompt reads "C2" I fly into high-gear removing the cuvette from the checker, closing the checker lid and whizzing open the cuvette cap. The reagent powder only takes about two seconds to pour into the cuvette after which I replace the lid and begin slowly swirling the cuvette making sure no air bubble are created all the while holding the cuvette up to a light source so I may watch the mixing progress. It typically takes right at 1:30 for the reagent to become completely dissolved and as soon as that happens I carefully clean the cuvette of any fingerprints, dust, etc then plop the little guy in the checker and hit the button.

 

I allow the checker to sit motionless for the entire duration of the three minute timer so as not to cause any air bubbles within the sample. Too, I never leave the lid open on the checker, itself ... ever ... and only open it to insert or remove the cuvette - all this to ensure the checker remains internally dust-free.

 

As with jservedio, I store the reagent packets in a separate location along with all other test items (Red Sea, API, etc) to ensure they do not become too warm. As far as measuring the sample I use a cheapie syringe (less needle) I picked up at my local pharmacy. I told the pharmacist tech what I needed and why and she magically produced a packet of 10 (5 ml) from behind the mysterious counter - $3 if I remember correctly. I also picked up three 10ml syringes from my dentist last week ... sans cost: I asked if she had any that size and why I wanted them and low & behold they ended up in my goodie bag at the end of the cleaning.

 

So yeah ... I seem to think the reagent could possibly have been spoiled. Some have mentioned it can take up to two minutes to pour the reagent powder ... this makes me suspect the powder is bad as it should readily flow - it takes mine 3 seconds *max*. Too, the same cuvette should be used for both C1 and C2 steps to ensure consistency. Next, along with the cuvettes requiring a totally clean surface the checker itself should be guarded to ensure dust does not enter the chamber as this could negatively affect the ability of the photometer within to properly sense light/colour. All in all I've found the unit I have to be remarkably consistent as long as I am careful when handling and processing the sample.

[jservedio]

I Figured out your Problem 100% - you have the wrong checker! You have the checker HI 713 which is only +/- 0.04ppm INSTEAD of HI 736 which is +/- 5 ppb. You have the "Low Range" instead of the "Ultra Low Range" checker. The checker you want reads out in Parts per BILLION not parts per million like yours does. I just checked BRS and realize they only sell the HI 713 anymore!!!

 

AquaCave has the proper checker (or you can buy it directly from Hanna) - you need to make sure the one you have is +/- 5 parts per BILLION instead of +/- .04 ppm (or 40 parts per billion).

 

The difference in resolution is nearly 10x... get the right checker and you will have good results! Don't buy the checker from BRS or MarineDepot since apparently they do NOT stock the CORRECT CHECKER!!!!

 

My checker is much, much more accurate than yours and it reads out in Parts per Billion. They are the same exact green and look the same except mine says "PPB" instead of "PPM" right above the display.

[ElmoC]

I Figured out your Problem 100% - you have the wrong checker! You have the checker HI 713 which is only +/- 0.04ppm INSTEAD of HI 736 which is +/- 5 ppb. You have the "Low Range" instead of the "Ultra Low Range" checker. The checker you want reads out in Parts per BILLION not parts per million like yours does. I just checked BRS and realize they only sell the HI 713 anymore!!! AquaCave has the proper checker (or you can buy it directly from Hanna) - you need to make sure the one you have is +/- 5 parts per BILLION instead of +/- .04 ppm (or 40 parts per billion). The difference in resolution is nearly 10x... get the right checker and you will have good results! Don't buy the checker from BRS or MarineDepot since apparently they do NOT stock the CORRECT CHECKER!!!! My checker is much, much more accurate than yours and it reads out in Parts per Billion. They are the same exact green and look the same except mine says "PPB" instead of "PPM" right above the display.

 

As I mentioned in my PM to you about it. I have both testers and I am using the correct reagents on each tester. I have some new reagents that should be here today and will run some tests with them and see how it goes.

[seabass]

You have the checker HI 713 which is only +/- 0.04ppm INSTEAD of HI 736 which is +/- 5 ppb. You have the "Low Range" instead of the "Ultra Low Range" checker. The checker you want reads out in Parts per BILLION not parts per million like yours does.

You're comparing 5 ppb of phosphorus to 40 ppb of phosphate.

 

AquaCave has the proper checker (or you can buy it directly from Hanna) - you need to make sure the one you have is +/- 5 parts per BILLION instead of +/- .04 ppm (or 40 parts per billion).

+/- 5 ppb of phosphorus = +/- 0.01533 ppm of phosphate (which we can then compare to +/- 0.04 ppm of phosphate).

 

The difference in resolution is nearly 10x...

It's more like 2.6 times, but it's still substantial.

[NanoTopia]

I have noticed that different reagent Lot#'s give very different results with the HI736 checker. It may be useful to indicate your reagent Lot# as well. One HI736 reagent I have had issue with is H025, I have sent 2 of these reagent packets to Hanna RI a month ago for testing in their lab, no word back. In any case I would avoid Lot# H025, if there are any still out there. I have found Lot# H030 to be (more) accurate thus far.

 

In addition, I have purchased a HI736 standard test, which I believe they are no longer producing, from the internet. I have used it 3 times to check my HI736 checker and got 80/82/80ppb respectively, the standard is certified for 100ppb. Which leads me to believe it is not just the reagents that vary in results, it could be the checkers themselves that are out of whack.

 

 

This is a stock photo showing the curvets half empty, not sure why, mine were full to the 10mL mark. Exp. 2016, do I trust it? NO. But I was curious to try it anyway for $10.

Final comment: These checkers are toys and should be treaded as such. They may give you a ball park idea of where your phosphorus is, or they may misguide you into thinking they are something they are not.

[jservedio]

You're comparing 5 ppb of phosphorus to 40 ppb of phosphate.

 

+/- 5 ppb of phosphorus = +/- 0.01533 ppm of phosphate (which we can then compare to +/- 0.04 ppm of phosphate).

 

It's more like 2.6 times, but it's still substantial.

 

How the hell do you get .01533ppm from 5 parts per billion? 1ppb = .001ppm.... x 5 and it is .005....

.04 / 10 = .004 which is very close to .005.... 1 part per billion off. So yes, the 736 is nearly 10x more sensitive...

[seabass]

Convert phosphorus to phosphate (to compare apples to apples) and see what you get.

[Mstefa1]

How the hell do you get .01533ppm from 5 parts per billion? 1ppb = .001ppm.... x 5 and it is .005....

.04 / 10 = .004 which is very close to .005.... 1 part per billion off. So yes, the 736 is nearly 10x more sensitive...

 

Simple math. To convert phosphorous which is the ultra low range checker you have mentioned to phosphate you need to take (phosphorous x 3.066) \ 1000.

 

(5 x 3.066) \ 1000 = 0.01533

 

Given that the phosphorous test kit is +/- 5ppb phosphorous in accuracy, this is equivalent to 0.015ppm phosphate in accuracy.

 

So compare the phosphorous checker converted to phosphate (0.04 \ 0.015) indicates that the phosphorus checker when converted to phosphate is 2.66 times more accurate then the phosphate checker.

 

But I guess that you didn't know that you were comparing phosphorous to phosphate.

 

Sorry for rambling on, I'm half asleep.

[ElmoC]

Okay. Got the new reagents and ran 3 tests. 27, 43, 53 ppb. This is just not acceptable consistency. They are marked Lot# H026. My previous reagents are also the same lot. So I don't know if it is a general problem with the lot or the tester.

[ElmoC]

Just ran a test on some salt water I made. Never been in the tank. Should be close to 0 phosphates. It tested at 22 ppb phosphorus or 0.06 ppm phosphate! Something is just not right here.

[Asureef]

I have lot #30 from Amazon, it seems pretty consistent so far. Today I ran 4 tests, results were 6ppb, 5ppb, 5ppb, 5ppb.

[seabass]

Just ran a test on some salt water I made. Never been in the tank. Should be close to 0 phosphates. It tested at 22 ppb phosphorus or 0.06 ppm phosphate! Something is just not right here.

Have you changed your DI resin lately?

[ElmoC]

I have lot #30 from Amazon, it seems pretty consistent so far. Today I ran 4 tests, results were 6ppb, 5ppb, 5ppb, 5ppb.

 

I just ordered mine through Amazon but got lot 26. There are several places that sell it through Amazon though. The one I got is listed as shipped and sold through Amazon. Shipping shows it came out of Nevada. Could be other warehouses have different lots. I wrote Hanna tech support about it. Will see what they have to say.

 

Have you changed your DI resin lately?

 

Given my RO/DI unit is only 3 months old, I would hope it hasn't gone that bad yet. Might grab some distilled water when I go shopping today and try mixing a small batch to test with using that water.

[seabass]

Sounds like a good test.

[NanoTopia]

I have lot #30 from Amazon, it seems pretty consistent so far. Today I ran 4 tests, results were 6ppb, 5ppb, 5ppb, 5ppb.

I have same Lot#, bought on Amazon, same results (5-6ppb).

 

[ElmoC]

I have same Lot#, bought on Amazon, same results (5-6ppb).

 

Why are you two getting the good lot but I'm getting the crap one?

[NanoTopia]

Why are you two getting the good lot but I'm getting the crap one?

 

Lot# H030 is reserved for TOTM winners

 

If you want consistently low phosphorus, ask for Lot# H030, but if they run out of that Lot# we will all have higher nutrients in our tanks again

 

See where I'm going with this ?

[ElmoC]

Okay. Got a gallon of distilled water and mixed it up to 1.023 and ran the test. 21 ppb. Either the reagents are bad or the tester is. I would expect the results to be no more than 5 ppb at most. But then, that is assuming the water was good to start with and no phosphorus in the salt. IO Reef Crystals.

[NanoTopia]

The test is designed for Marine water, not fresh water, you will not get accurate results using it to test RO water (or marine water), sorry to say.

[ElmoC]

The test is designed for Marine water, not fresh water, you will not get accurate results using it to test RO water (or marine water), sorry to say.

 

Did you read the part where I said I, "mixed it up to 1.023 and ran the test."? I made it marine water before running the test.

[Mstefa1]

This sounds like a stupid question... But did you try changing the battery (even if it doesn't say low battery)?

 

What does Hanna have to say?

[ElmoC]

No. didn't try changing the battery. When I first contacted Hanna, their response was to get the 736 for better low-end reading. Some help that was. Still getting inconsistent results. Might try running a few tests with a new battery later.

[NanoTopia]

Did you read the part where I said I, "mixed it up to 1.023 and ran the test."? I made it marine water before running the test.

Sorry, I no read good