Salifert phosphate test kit

[bertoni]

I agree that the Hanna seems to give consistent numbers, but consistency isn't the same as accuracy. It'd be nice to have some actual data on the accuracy of the various products, but it'd be expensive to generate and require ongoing work, since the kits can vary from batch to batch.

My belief is that the accuracy of any test kit or meter is questionable at any time, so it's best to tread carefully when a kit says something is off.

 

[chercm]

I agree that the Hanna seems to give consistent numbers, but consistency isn't the same as accuracy. It'd be nice to have some actual data on the accuracy of the various products, but it'd be expensive to generate and require ongoing work, since the kits can vary from batch to batch.

My belief is that the accuracy of any test kit or meter is questionable at any time, so it's best to tread carefully when a kit says something is off.

the pain here is that when we bring up issues like the powder getting stuck on the side of the viral , powder not dissolving causing high readings which a lot of us getting out of range results and hanna is not replying .

 

[chercm]

I've no issues with the Hanna PO4 egg and consistent results over multiple tests on the same sample. I stated that in the previous post. The calcium checker is another story all together.
Having watched plenty of other people using the PO4 checker at group meetings, I have noticed many people have difficulty adding the powder reagent, which in turn gives false readings. My misspent youth gave me an advantage in this area.
This common difficulty with adding all the reagent, problems with adding the correct amount of sample, discoloured glass, external contaminants on the cuvet, scratches/fingerprints on the cuvet, issues with time outs, particles in the sample and a whole other host of simple mistakes that can give false readings makes the Hanna PO4 egg less than perfect in its simplicity.
I love my Hanna PO4 egg but they are no easier to use than the Salifert kit. If anything I find the Salifert kit simple to use and great value. I've used both for some time now and will continue to do so.
The OP will do just fine with the Salifert kit until they want a new toy to play with.

just need to check i used the water from the display and every time there is some particle in the water and it is glass here so there is bound to have scratches . please advice how to handle this

 

[Rosscopeco]

This thread is probably not the best spot for product resolution.
All of the tests I've seen have the same problems you mention in varying degrees. Learn to use them like a lab tech.
I'm sorry there is no easy solution. Liquid reagents aren't suitable for all tests.

 

[Rosscopeco]

just need to check i used the water from the display and every time there is some particle in the water and it is glass here so there is bound to have scratches . please advice how to handle this

Glass does not need to have scratches and the water should not contain particles. I understand that the sample water may contain particles but those should settle out in the three minutes specced by Hanna.
If you have particles of the reagent then you need to keep mixing.
If you have lots of detritus stirred up in your tank then it's time to wait before testing. Another trick is to take a container of sample and let it settle out before testing.
I'll try again tomorrow but I've never had too much discrepancy with the Hanna PO4. The Salifert agrees.

 

[tmz]

I use both the hanah chlorimeter( older full size 713) and the salifert test kit. I test PO4 daily( obsession) with the colorimeter and have for over 3 years. It is very consistent . Consistently low ph is what I'm after in my tanks. Rarely,once in a hundred tests or so I get a reading that's .02ppm or so off the norm of .03/.04 .Turns out to be a curvette ,wet on the outside or in some cases a bad reagent pack;did have a few bad packs of these a couple of years ago but not now. I'll retest' after wipng down the curvette and the receptacle ; it returns to normal readings .
I know that's not data but is relaible performance.
So is the normal reading of .04ppm I get really .04ppm or is it .08ppm or .00pm due to the range of accuracy? I think its more like .04ppm most of the time, that is I think the readings I'm getting are not .04 ppm off except on rare occassions due to the consistency experienced and the fact that newly mixed salt tests at 0 ppm while tank waer tests .03/.04/.05ppm.

The salifert test kit works well down to 0.10ppm for me and my eyes but I can't get more out of it with any confidence. It will often show what looks like 0 and the colorimeter will show .04 or more.

 

[Rosscopeco]

Is that with the low range test on the salifert?

 

[tmz]

For . the phosphate meter much of the reagent powder normally remains undissolved after a 20 second swirl. After that step , I remove the cap and wipe the top in case of a leaky drop.


I draw sample water and couple of inches down off the surface with a large baby dosing dropper , rinsing the curvette out once or twice and then examining it under a light for any visible particulates. Some recommend using filter paper but
I haven't found that to be necessary.

The curvette is handled with a dry paper towels through every step and rinsed thoroughly within minutes of each use to prevent staining from the reagent. It is not scratched . If it were, I'd use a new one.

 

[chercm]

For . the phosphate meter much of the reagent powder normally remains undissolved after a 20 second swirl. After that step , I remove the cap and wipe the top in case of a leaky drop.


I draw sample water and couple of inches down off the surface with a large baby dosing dropper , rinsing the curvette out once or twice and then examining it under a light for any visible particulates. Some recommend using filter paper but
I haven't found that to be necessary.

The curvette is handled with a dry paper towels through every step and rinsed thoroughly within minutes of each use to prevent staining from the reagent. It is not scratched . If it were, I'd use a new one.

do you mean after the 20 sec swirl the particles not dissolved , you still put into the device ?

 

[tmz]

do you mean after the 20 sec swirl the particles not dissolved , you still put into the device ?

Yes

 

[tmz]

Is that with the low range test on the salifert?

Both the standard and double sized. Haven't used it for a crosscheck to the hanah in a while ,so, I did it today. Salifert both tests not a tint of blue that I could see. Hanah both tests .04ppm.

 

[jcw]

Both the standard and double sized. Haven't used it for a crosscheck to the hanah in a while ,so, I did it today. Salifert both tests not a tint of blue that I could see. Hanah both tests .04ppm.

This is not comforting news...

Salifert has colors starting at 0.03 at standard testing amounts. Double the water and reagents and they claim double the resolution which means you should be able to see some color change 0.015.

I thought that even if phosphate was 0.05 if I doubled the reagent the color should be easily visible.

Apparently not...


Looks like I'll be investing in a Hanna checker.

TMZ, and the other Team RC leaders, if you were to buy a phosphate kit again, would you get the hanna colorimeter?

 

[jcw]

Both the standard and double sized. Haven't used it for a crosscheck to the hanah in a while ,so, I did it today. Salifert both tests not a tint of blue that I could see. Hanah both tests .04ppm.

At your current phosphate level, are you having issues with nuisance algae? or coral color problems?

 

[tmz]

No, not at all ,almost never see nusiance alge or cyano and it's an sps dominant mixed reef.. You can judge the color question for your own tastes by looking here :

November Tank of the Month

 

[karsseboom]

But I didn't make any claims about accuracy.

We don't really have much data on how accurate any of our test kits are, except a tiny bit for the Hach, so I wouldn't make any assumptions about accuracy. It's easier to get a number from the Hanna, but it might be very far off, for all we know.

There was an article posted where they tested an lab grade low range p04 test to a hanna checker. The result was very close, they also did back to back tesing with the alk one and found it was pretty far off.

here it is http://www.advancedaquarist.com/2011/8/review

 

[Rosscopeco]

Both the standard and double sized. Haven't used it for a crosscheck to the hanah in a while ,so, I did it today. Salifert both tests not a tint of blue that I could see. Hanah both tests .04ppm.

I did the same myself but had no difficulty seeing the blue tint that let me know it's time to change out the Rowaphos. I would agree that the blue tint is ever so slight at those levels and under certain lighting conditions it would be impossible to tell the difference.
I'll have another crack at it today to see if I can repeat the results.
PS.
I was reading your suggestions on doing the Hanna Po4 test. I know it's probably a typo but the suggested mixing time is 2 minutes as far as I know.
I also remember your puddles from the article. Nice work.:thumbsup:

 

[chercm]

do you mean after the 20 sec swirl the particles not dissolved , you still put into the device ?

Yes

will it not create false high readings ?

 

[Rosscopeco]

After the 120 second swirl, there shouldn't be many particles left.
The particles should settle out in the three minute period anyway.

 

[tmz]

I did the same myself but had no difficulty seeing the blue tint that let me know it's time to change out the Rowaphos. I would agree that the blue tint is ever so slight at those levels and under certain lighting conditions it would be impossible to tell the difference.
I'll have another crack at it today to see if I can repeat the results.
PS.
I was reading your suggestions on doing the Hanna Po4 test. I know it's probably a typo but the suggested mixing time is 2 minutes as far as I know.
I also remember your puddles from the article. Nice work.:thumbsup:

No it's not a typo. I have the 713 full sized model. Don't know what the checker directions may state but don't see why 2 minutes of swirling would be at all necessary or helpful and may throw the test off either by bubbles accumulating or just from the extended amount of time the reagent is in the sample .. Where did the 120 seconds come from?

The directions I have state: " replace the cap and shake gently.".. reinsert the cuvet into th isntrument"... It's more important to get th sample read clsoer to the 2 to 3 minute timeframe. 3 minutes at 20C/ 68 F or about 2minutes at 26 C / 79 F. By the end of the reading period there isn't much if any reagent left.

This was discussed extensively on the Chemisty forum in the past . For the 713 reagent ,just a brief 20 second swirl is all that is required. Maybe it's different for the others but I don't see why it would be.

Glad you saw the Puddle article. thanks

 

[tmz]

To answer a question posed to me in an earlier post.
I would definitely go with the hanah over a the commonly available test kits. Never tried the Hach; it's pricey. .Even if the hach has .03ppm accuracy rating the newer hanahs have a better accuracy rating than the older model and can match or surpass .03ppm accuracy , IIRC.

On another issue, I had problems trying to figure out how to get the reagent from a packet into the cuvet neatly at first. Now, I snip off one end of the alumium foil packet with scissors. Then I pull it open into a flat rectangle. Crease it in the middle lengthwise and use it like an open funnel to slide the powder into the sample. Easy.