Hannah HI713 questions
 

Just it the Hannah phosphate checker and am reading the directions and just a bit confused.

10ml of unreacted sample. Is this just tank water with no reagent?

Also I heard about the instrument timing out to fast between samples. Should I mix the reagent in before starting the test with the unreacted sample so I don't timeout?

So nobody has ever used a Hannah checker all the sudden

yes the sample is just tank water, no reagent. you have to 0 out the checker 1st before adding in the reagent, if it is the new checker then it has a longer timeout so you should be good, if it does have the short shutoff you may have to try it 2-3 times to get it but after you figure it out it's easy enough to do without having it time out on you. a good trick is to get the reagent already open and ready to pour in as soon as it is zero'd out. also try to keep the test tube in the same direction each time.

So you don't use the second tube for water with reagent? The directions just say to add the unreacted sample in and wait til it says c2 then to added the reacted sample. It states that the reagent takes two minutes to dissolve and also states it will timeout at two minutes. That is the reason I thought one tube for straight tank water and the other for water with reagent.

Maybe I am just over thinking it. But now I feel even more confused

I would not use 2 tubes for the measurement. There may be a slight difference in the glass and the results are not accurate. This is how I do it. I open the bag and prepare it for removing the powder to the tube. After you insert the tube with the tank water, press the button to turn it on and then press it again. After a few seconds you will see C2 on the display. Add the powder to the tube and turn on your timer for 2 minutes. I always mix it in steady movements for 1 min and 40 seconds. It never times out.

So what is the other tube for??? Just for fun

only use 1 tube for accuracy reading. pratice few times you will be good

the 2nd tube is there for a spare

Also you need to give it time for all the micro bubbles to rise. You won't really be able to see them but if you hold it under your tank lighting, you'll see them. Give it a couple taps on the bottom of vial to dislodge bubbles from sticking to the side. Too many bubbles can give you an inaccurate reading. Also make sure the outside of vial is clean... No water, fingerprints, lint, etc

So I setup a stopwatch and got 3:13 before it times out. I also ran two tests and got 0.09 and 0.07. The first one I don't think was accurate as I rushes it and don't think all the reagent dissolved.

If you read the directions closely...those two test results are equivalent given the standard error of the instrument...you must have good technique...nice work. :)

i agree, your within the +/- of .03 range of these checkers so your doing it correctly

If you press and hold the button down after c2 you can activate the 3 minute count down timer.

so if you're getting 3:13 seconds before it times out push and hold the button down. This will get you another 3 minutes. you can shack gently for 2-3 minutes then push and hold the timer, put the vial in, and the checker will count down 3 minutes before it reads. This will give you time for the micro bubbles to float out.... you can also give it a few gentle taps on the table to help release the bubbles.....

go to you-tube there are manufacturer videos there....

Really thought the numbers would be lower given I am running GFO through a BRS reactor and also running an algae scrubber.

Is all relative to your nutrient input, and/or phosphate in the rocks. Or even a recent moving of rocks, which will kill the periphyton on them.

I use both vials to run the test. I ran numerous "tests" with both vials using RODI in each and never recorded any variation in results, always zero. Using two vials makes it possible to run the test twice (without another settling 3 minute countdown on the second test) and interpret the two results. I have also noted that my Hanna sometimes take 30 seconds 'tween C1 and C2 and sometimes only 4-6 seconds. The results don't seem to change but the timing changes.

My nutrient input is fairly minimal. I feed half a cube a day. Sometimes a little less. I would imagine it is leaching out of the rocks even though this system was set up 9 months ago.

Is it possible for my phosphate levels to drop to 0.02. On Sunday I changed out 15 gallons of water and replaced te GFO with 1 cup of fresh. Is that really possible or was my test off??? My system is approximately 250 gallons so a 15 gallon change isn't really significant

it is possiable, GFO pull out phosphate fast and will also get used up fast, sometimes within a day it needs to be changed. your best bet is to test the output levels of the GFO reactor and that will tell you when you need to change it.

also going by your numbers and the accuracy of the checker it may not have dropped much at all as your .07 could actually be .1-.04 and your .02 reading could be .05-.00. but if your getting a reading of .02 your good to go.

Bring this back to life.


Just ran 3 consecutive tests all 3 came out 0.00.

test your tap water, If you're still getting zero, you got a problem....probably the reagents.

I use both vials with the 3 minute countdown on the first test and two more quick tests without the countdown. Three results, two are usually the same results with one off by +/- 0.01. I use the average of the three results. I am less concerned about the actual number than the trend. I test every 3-4 days. I can't figure if the published Hanna .04 error is a consistent or a variable event.

Reagents are brand new just ordered them a few months back.

could be a bad batch. I have never had a bad batch but some people on RC have

Got a new box of reagents today and still getting a 0.00 reading. Could my checker have gone bad?