Disappointed with hanna phosphate tester

[Robink]

No complaints here. I use the hanna checkers for p04 and alk. alk I check every day and p04 once a week.

 

[Kershaw]

Mine goes from 00 to .14 to .03 then 0 after that. Maybe I will contact hannah

 

[jason2459]

I have read and followed. But the powder dose not fully dissolve unless I tilit it up and down for about 4 or 5 minutes

Possibly bad reagent. I know the ULR reagent mixes in better. But with either I've had no issues getting them mixed in time. And if there's a tiny bit undissolved Hanna has stated that it is fine.

 

[Graffiti Spot]

Guys there was a bad batch of recent for a while. They would read inconsistent and high. The new ones that have been out recently are good.

I hold the button to turn on the three min timer and shake the vial hard to dissolve the powder quickly. Then with a min left I swirl it around to get any microbubbles off the sides and wipe it clean with about 30 seconds left and let it sit for the rest of the last 30 seconds. I get almost exact readings every time. And my phosphates are around .1 which is pretty good for one that's supposed to read low range. It reads co distant when I had phosphates near 0 as well.

Where did you guys read your supposed to let the vial sit for 3 min after mixing?

 

[Kershaw]

Guys there was a bad batch of recent for a while. They would read inconsistent and high. The new ones that have been out recently are good.

I hold the button to turn on the three min timer and shake the vial hard to dissolve the powder quickly. Then with a min left I swirl it around to get any microbubbles off the sides and wipe it clean with about 30 seconds left and let it sit for the rest of the last 30 seconds. I get almost exact readings every time. And my phosphates are around .1 which is pretty good for one that's supposed to read low range. It reads co distant when I had phosphates near 0 as well.

Where did you guys read your supposed to let the vial sit for 3 min after mixing?

I don't think anyone said let it sit for 3 minutes. We only have 3 min to get reagent dissolved before unit shuts off. And we also said you hold the button until the 3 minute timer starts

 

[jason2459]

I never shake. Gently tip over and back for a couple minutes and then spin slowly on its side to remove any build up on the sides. Not touching the vial the entire time. Then press amd hold the button to get 3 minute timer. Always placing the vial into the checker with the 10ml label facing forward.

The 3 minute rest will allow for reaction time and for anything undisolved to settle and microbubbles to rise.

 

[jason2459]

From my PO4 kit shootout on how I perform the test

First up is my current favorite and go to. The Hanna 736 ULR ppb Phosphorus Checker. I feel I get consistent results and accurate enough for tracking my phosphates and to know I'm in my target range. But I'm not going to be so close minded that there can't be or hasn't been issues with this checker for other people.

BeanAnimal did an excellent review on it as well. He wasn't so impressed and experienced issues with bad reagents. Which can be an issue with any test kit of any brand for any kind of test.
http://www.beananimal.com/other/hanna-hi-736-checker-hc-opinion.aspx

Cost wise its upfront cost is more then some others at around $40-$50 but the long term cost is reduced by being able to just buy the reagents for like $8 for 25 packets.

This technically is a phosphorus checker so to get the phosphate numbers we commonly look for and recommended to be at around .03ppm or below there's some math to be done. There's a chart in that link above already breaking it down or just remember to

Number in ppb x 3.066 and then divide that by 1000 and you will get close enough to what you are looking for with phosphates in ppm.

For accuracy it's pretty good with a range of 0-200ppb, resolution of 1ppb, and an accuracy of ±5 ppb ±5%. Which is really pretty good if it matches what's advertised.

Which Hanna sells what they call a calibration set but you can't really calibrate the Checker. You can however use it to check the accuracy. But there is a flaw with this one in that it uses two vials. Which if there are in flaws and differences between the two vials either initially or over time with use it will cause interference making the readings inaccurate.

I did this "calibration" set for the ULR phosphorus checker and have used it a few times to check accuracy of my particular ULR Checker. So, far I've gotten readings of 98 a few times and 100 a few times. Which is about as good as I could expect to get. The reading is supposed to show 100ppb ±10 ppb or anywhere between 90 and 110. Tonight the reading was spot on 100.

Now for testing my tanks water. I have a pretty good routine down with this checker and do the same with the 713 checker as well.

1. rinse out the vials with tank water several times
2. Fill with 10ml of tank water
3. Get a packet out and flick it a few times to loosen up the powder and move away from the area I'm going to cut in a curved pattern as indicated on the packet (was doing this before they put that indicator on there as well)
4. Set the vial down with tank water and wait for 4-5 minutes doing other stuff
5. Turn the checker on and wait for it to ask for C1
6. Place the vial in with the 10ml mark facing me
7. Cut open the reagent packet and pinch it open so the bottom part is creased to help funnel the powder out into the vial
8. Press the button to read C1
9. As soon as it asks for C2 I pull the vial out (never touching with my fingers at any stage of this using a lint free cloth) and add the reagent
10. Close the vial up and look at the time and gently start mixing the reagent into the water. Taking care not to form bubbles on the insides of the glass.
11. Gently turning over and swirl to mix for 2 minutes.
12. Place sideways and roll the vial to allow air bubble in the vial to remove anything on the sides. Again, never touch the sides with fingers.
13. Press and hold the button for 3 minute timer
14. Place the vial back into the checker with the 10ml mark facing me and wait for the 3 minutes to count down.

I find that the reagent for the ULR 736 checker dissolves a lot better then the 713 Low Range checker. Also the end result value is displayed a lot longer on my 736 ULR checker.

And the results tonight are on target with the range I am usually in.

11ppb phosphorous converts to 0.03ppm phosphates.