Hanna ULR replacement?

[West1]

As of late I’ve been having some issues with my 736. I’m curious if spending the extra cash on the MI412 (which would be cheaper in the long run w/reagents) would be a wise move?
I prefer the 736 because it’s30% more accurate than the newer 774.

Not much info on here about the Milwaukee other than a few comments.

I’d love to hear some reviews!

Tyvm

 

[disaster999]

What issues are you having with it? I have the ULR 736 and Im questioning its accuracy and dont really want to waste reagents at ~$1 a packet just to test out my theory.

 

[West1]

What issues are you having with it? I have the ULR 736 and Im questioning its accuracy and dont really want to waste reagents at ~$1 a packet just to test out my theory.

I can’t get a consistent reading.
I have a total of 8 Hanna Vials and I’ve now tried to use each one for the 736 test.

I clean them w/RO and place a napkin inside each to absorb any leftover water (I now rinse w/tank water prior to running a test). My readings range from 0.00-33ppb on the same vial w/reagent! W/mixed reagent, I use a separate vial as the calibration then the mixed reagent from the prior reading to test the last 736 reading of the same reagent… it’s never the same. I insert each vial the same, 10ml facing the black button for consistent readings.

I emails Hanna and they sent me a guide to doing the test followed by my 736 is out of warranty. I’m happy they sent that because I was going to buy the Hanna master checker (9 different test) and after that reply, I’ll look elsewhere.

I’m on day 3 of checking w/correct Reagent as I purchased the 774 and I can’t get a consistent number. Batteries changed and checked w/a multimeter.

 

[disaster999]

I have similar issues. I have 2 Hanna vials so I decided to test the repeatability of the Hanna tester. I filled 1 with tank water and the other with tank water + reagent and did 10 readings to see what were the results. I was surprised how vastly different the readings are ranging from 21 all the way down to 3 and anything in between. I know this will not give an accurate measurement, but at least this will tell me how accurate and repeatable the results are..and apparently its not very accurate or repeatable.

 

[gbroadbridge]

I have similar issues. I have 2 Hanna vials so I decided to test the repeatability of the Hanna tester. I filled 1 with tank water and the other with tank water + reagent and did 10 readings to see what were the results. I was surprised how vastly different the readings are ranging from 21 all the way down to 3 and anything in between. I know this will not give an accurate measurement, but at least this will tell me how accurate and repeatable the results are..and apparently its not very accurate or repeatable.

Are you guys ensuring that there are no bubbles on the inside of the cuvette before putting into the checker?

Remember, you're not supposed to shake the cuvette after adding the reagent, just gently invert for 2 minutes so as to not introduce air into the sample.

Before putting into the checker invert gently a couple of times to dislodge any air bubbles, clean the outside of the cuvette with a microfibre cloth and then insert into the checker.

I find the checkers to be very consistent and reliable as long correct laboratory technique is used.

 

[disaster999]

Are you guys ensuring that there are no bubbles on the inside of the cuvette before putting into the checker?

Remember, you're not supposed to shake the cuvette after adding the reagent, just gently invert for 2 minutes so as to not introduce air into the sample.

Before putting into the checker invert gently a couple of times to dislodge any air bubbles, clean the outside of the cuvette with a microfibre cloth and then insert into the checker.

I find the checkers to be very consistent and reliable as long correct laboratory technique is used.

Yes, there are no visible bubbles inside the water or clinging onto the sides.

 

[West1]

Are you guys ensuring that there are no bubbles on the inside of the cuvette before putting into the checker?

Remember, you're not supposed to shake the cuvette after adding the reagent, just gently invert for 2 minutes so as to not introduce air into the sample.

Before putting into the checker invert gently a couple of times to dislodge any air bubbles, clean the outside of the cuvette with a microfibre cloth and then insert into the checker.

I find the checkers to be very consistent and reliable as long correct laboratory technique is used.

I use a small magnetic stirrer, not sure it pulls air into the mixing sequence. I’ll have to check

 

[gbroadbridge]

I use a small magnetic stirrer, not sure it pulls air into the mixing sequence. I’ll have to check

I would not be using a magnetic stirrer for a few reasons.

The reagent dissolves readily without mechanical aid.

You're introducing a violent method of stirring using a bead introduced in a tiny volume of sample together with possible impurities.

How do you remove the bead before measurement as its presence is probably reflecting light within the optical system.

And finally, the instructions are quite clear on the correct procedure.

 

[Salty_Northerner]

I can test mine 10 times in a row and get the same exact numbers so something's going on with your unit.

Also I just use rodi water when cleaning out the reagent and empty it into a container and then refill with rodi and then cap it and store it away till next use. I empty the glass vial and give it a good shake to get any water out then I just have a small container with test water that I'll use, a pipette to fill it up to the line and I make sure I have the 10 mL pointing towards the front every single time I do a test just in case there's any inconsistency within the glass. I've done it myself by putting a paper towel or something in that manner to dry inside of the vile but all it does is leave faint markings inside the glass so that's why I always store it with fresh water and don't stick anything except basically a pipe cleaner brush that can be twisted inside the glass to get any residue off inside.

Went shaking I just put it on my four finger and thumb and gently rotate my wrist back and forth kind of like creating a wave with inside the glass vial.

 

[jda]

I can also test many times in a row and get the same number (within one or two).

Use 2 vials. Powder into one vial, the other with nothing. I shake the heck out of the one with the powder - the bubbles all go away in time. Wipe them down clean until the outside of the glass sparkles. Use the three minute function. You can retest if you grab them after the 3 minutes, just don't use the three minute timer the second time. The second test can be a bit lower than the first, but it is usually very close.

25 tests for $13 on eBay. Buy a few and the shipping does not go up.

 

[West1]

Thanks for the feedback all, I will try and run a few test without a magnetic stirrer. Hopefully that solves my problem. I also ordered a 736 calibration set just in case.

 

[West1]

I would not be using a magnetic stirrer for a few reasons.

The reagent dissolves readily without mechanical aid.

You're introducing a violent method of stirring using a bead introduced in a tiny volume of sample together with possible impurities.

How do you remove the bead before measurement as its presence is probably reflecting light within the optical system.

And finally, the instructions are quite clear on the correct procedure.

Did as you suggested… 3 packs of reagent and 3 different results. 0, 12, 4. Once I got the reading, I marked each vile and wrote them down. With a 4th vile, I used that one as C.1 for the following 3 readings… Vile 1) blinking 0, 31, 7
Vile 2 (the 12ppb), 0, 0, 17
Vile 3 (the 4ppb), 21, blinking 0, 4

I’m going to guess the unit is bad. I’ll be able to verify when the calibration 736-11 comes in.
Between now and then, I just hope I have some po4 in my tank as they bottomed out a couple weeks ago then I overdosed using the 774 reagents. Now idk where I’m at other than SPS dead, bleaching and now possibly holding still (and hopefully ready to heal!).

Been using a magnetic stirrer for roughly 3+ years on the 713, 736, copper and dkh Hanna checkers but, I did leave room for that possibility. I’ve always got consistent numbers within tolerance. Which is how I realized there could be a problem, “clear instructions” or not.

 

[gbroadbridge]

Did as you suggested… 3 packs of reagent and 3 different results. 0, 12, 4. Once I got the reading, I marked each vile and wrote them down. With a 4th vile, I used that one as C.1 for the following 3 readings… Vile 1) blinking 0, 31, 7
Vile 2 (the 12ppb), 0, 0, 17
Vile 3 (the 4ppb), 21, blinking 0, 4

I’m going to guess the unit is bad. I’ll be able to verify when the calibration 736-11 comes in.
Between now and then, I just hope I have some po4 in my tank as they bottomed out a couple weeks ago then I overdosed using the 774 reagents. Now idk where I’m at other than SPS dead, bleaching and now possibly holding still (and hopefully ready to heal!).

Been using a magnetic stirrer for roughly 3+ years on the 713, 736, copper and dkh Hanna checkers but, I did leave room for that possibility. I’ve always got consistent numbers within tolerance. Which is how I realized there could be a problem, “clear instructions” or not.

I agree it could possibly be the checker.
If you get inconsistent readings with the blue tinted water that'll prove it.

I can run multiple tests using a 250ml water sample taken from the tank and see no more than 0.01 variance on my ULR phosphate checker.