Let's talk about the hanna meters....

[brahm]

I'm using the phosphate one, so far I've had good results I've done single vial, and 2 vial. Only got 0.00 one day. Basically, my results so far have been. Overtime, I've done water changes, moved my ecobak pellets to a reactor, and have noticed a steady drop into Nitrates, and phosphates until I added some sps that rtn'd the day I received them and saw an increase. I've got not reason to believe it's any less accurate then any test kit I used or the variation of the colours in the vial based on the angle of the light hitting it how many lights are on in the house, ect ect.

My results w/the hanna phos
9/23 - .58
9/28 - .4
10/3 - .21
10/7 - 0
10/12 - .04

 

[Troylee]

im gonna go do my nasty tap water now...brb

 

[Troylee]

ha vegas city tap water...850 tds
and............







ready!!!!!!!!!!!

 

[gilmour01]

Do i need special glasses to read the Hanna Reps posts? i think i still have my Avatar glasses around here somewhere if that would help me to see their responses.

 

[Troylee]

well i will just start using my tap water for wc. .09 is acceptable to me for a aquarium.... lol

 

[tjw00]

TJW, if you have enough packets, try giving your tap water a test and see what it says. We have good water here in SLC, but 0.00 phosphates??? I don't think so.

I'm not trying to be a smart butt (kinda sounds like it). I'm serious, I'd be curious to see what results you get.

I tested my tapwater a few days ago and posted the results in this thread . (probably a few pages back by now) . The Hanna meter, salifert and API all agreed on about 1.5 ppm which is close to what NYC says is in the water( they intentionally maintain 2ppm as a pipe corrosion inhibitor). My Tds out of the tap is 45.

 

[Troylee]

Just checked the vegas water quality report and it doesn't show or they didn't test for po4 levels...
There is no way it's .09 maybe I just got a bad meter or some bad regents....

 

[jcom]

All I know is it rendered this test untrustible in my opinion so even though at this point even though I'm hating giving hanna anymore money I'm thinking of giving them $10 for the test to see if my meter has the same problem what I'd really like to know is why don't they give us one for free with the meter

....or not charge $10 for one reference test. How about a nice sized bottle of 1.00 sample. It's a joke.

 

[jcom]

Just checked the vegas water quality report and it doesn't show or they didn't test for po4 levels...
There is no way it's .09 maybe I just got a bad meter or some bad regents....

I don't think yours is an isolated case.

 

[sowellj]

I've been reading/skimming this and I'll throw in my two cents. Here is my disclaimer ... I don't own the meter but I am a chemist and know the chemistry behind how it works. It is basically like any other test kit ... you add a reagent that reacts with your analyte (phosphate in this case), and get a color change. With most kits your eye is the 'detector'. In this case you shine a light through your sample and measure concentration by how much of that light was absorbed. This is called beer's law. UV-Vis Spectroscopy is the generic name of the technique. I don't know if I will add anything new here ... but, clean cuvetters are critical. Otherwise, you get light scattering that can throw things way off. I would use alcohol to clean the curvetters as water may only smear fingerpring oil. Since these are most likely not lab grade cuvettes it is likely better to use the same one for zeroing as you do for measuring. Generally speaking, Beer's law is only linear over one order of magnitide. Whether they take this into account or not in their calibration I don't know. Also your absolute error is going to scale linearlily with concentration. Percent error (error in relation to the concentration reading), will be higher at the low concentrations. Other variables that could potentially affect things would be temperature (minimal effect) and reaction time.

 

[kev2me]

Here's what she said over on RC:

Hello everyone, thank you for your patience while I conferred with the chemistry department. There have been several issues raised, and I will do my best to address them all here. Please let me know if I have missed anything or not explained it to your satisfaction.

This brings up some interesting problems for hanna chemists.
1) Can you design a the regent to effectively change based on the amount of the chemicals you are testing in the sample.
2) Are these compounds stable over time.(this is I think why the regents are individually packaged)
3) How is this reaction influenced by things such as temp and ph and all of the other things in the sample.

1) Yes. Each photometer has a specific range, which dictates the amount of reagent used for that test.

2) Yes. Each packet is stamped with an expiration date. Powder reagents are generally shelf stable for at least a couple of years.

3) We have used specific compounds to negate pH and temperature interferences.

Regarding the method:
Obviously, we cannot release proprietary methods/chemicals for our competitors to copy. This is why the MSDS for any product of any instrumentation company only gives the necessary safety information.

When designing the HI 755, our team used Standard Methods for testing total alkalinity as the reference method. Every HI 755 we have shipped and all the reagents lots were exhaustively tested against standards for total alkalinity, using commercially available artificial seawater, with a laboratory grade auto-titrator. Several hundred titrations were performed, and the HI 755 was dead on accurate every time.


Regarding the caps:
Anyone with a leaking cap, please send me a PM and I will take care of it.

Regarding the reagent packets:
You have all made some excellent suggestions on how to improve this. We are already looking into alternative packaging, but making this kind of change takes research and time.

We take all your concerns and suggestions very seriously, and we want nothing but satisfied customers. The chemistry department is at this very moment testing several commercially available alkalinity test kits and at least one standard that are used in the marine aquaria hobby, to verify their accuracy with an auto-titrator. We are confident in the accuracy of the meter we have produced, and hope that the data we produce today will assuage any doubts the exist.

Thanks
Jessica

 

[Troylee]

Okay a quick update guys... Jessica just shot me a email and said hopes to be on very soon even promised..
She has some issues with a sick kid right now so when she gets a chance, she will be on to help us.....

 

[Mr Beardsley]

ha vegas city tap water...850 tds
and............







ready!!!!!!!!!!!

Why would you think that just because you have high TDS you have high phosphates? You might have water that has a lot of carbonate hardness leading to a high TDS, but there may or may not be a lot of phosphate. Unless you check your tap water against another test I don't think using TDS can really show how accurate or inaccurate is the tester.

 

[ReeferRob]

Ha my Hanna just gave me a .78 reading with not a single thing in the unit??? I thought I'd mention that I've never once got a zero reading out of my little green egg.

 

[FISH PROS]

so where is the HANNA REP? oops didnt see troylees previous post

 

[Troylee]

Why would you think that just because you have high TDS you have high phosphates? You might have water that has a lot of carbonate hardness leading to a high TDS, but there may or may not be a lot of phosphate. Unless you check your tap water against another test I don't think using TDS can really show how accurate or inaccurate is the tester.

Oh I agree completely... It's not a true test because I don't know what our tap water contains or anything... I just find it hard to believe after seeing another tap water tested and the results showed .58 from salt lake city I beileve it was, where they are known for great water quality... Someone in my local club has a big Hanna I'm trying to figure out who it was and compare the 2 side by side...

 

[Oiseau Reefer]

I tested my water with the hanna egg and got a .08 then with an API and got in the .5 range and yes I know the API test kit isn't the most accurate but hey that's still a huge range

 

[jcom]

Oh I agree completely... It's not a true test because I don't know what our tap water contains or anything... I just find it hard to believe after seeing another tap water tested and the results showed .58 from salt lake city I beileve it was, where they are known for great water quality... Someone in my local club has a big Hanna I'm trying to figure out who it was and compare the 2 side by side...

Troylee, correction. I tested my tap water in Salt Lake City and got a 0.00 Is it possible that there are no phosphates in SLC tap? I guess, nations top rated water, but 0.00??? Really???

 

[Troylee]

Well I had another local test the tap water and he got .18 is it possible to have different readings around the valley??? I mean I guess it is... Just so many in answered questions...

 

[sowellj]

Well I had another local test the tap water and he got .18 is it possible to have different readings around the valley??? I mean I guess it is... Just so many in answered questions...

Hey Troy ... If you are interested I could make up some standards for you at a few different concentrations and mail them to you. I don't see a reason why I could not use sodium phosphate. I am off this week as my wife and I had our first child, but I will be back in the lab on Monday.