hanna phosphate checker

[Cal_stir]

I tested my tank today, 0.00ppm, I was skeptical so I did it again, 0.00ppm, still skeptical so I tested untreated tap water, 0.00ppm, now I'm very skeptical so I added .4ml micro algea grow to the sample(which I know contains phosphate)0.61ppm, still very skeptical as I expected a much higher result but I don't know how much phosphate it contains, so I mixed a sample with 75% tap water and 25% miracle grow that is 4% phosphate by volume, so I figure my sample is 1% phosphate by volume which should equate to approx. 10,000ppm, 0.14ppm.

now I have read the instructions 10 times and I am definately performing the test correctly so either the hanna checker is a total piece of crap or I am missing something.

anybody have any suggestions?

 

[phi delt reefer]

Checker has an accuracy of plus or minus 0.4

 

[Blob-79]

ya something doesnt seem right. it should be impossible to reach 0.00 phosphate in a fish tank. You are calibrating it with a fresh sample of water in your tank?

If you are sure you are doing the tests properly, I would return the checker because it sounds defective.

phi, the accuracy of the hanna checker is =/- 0.04

 

[phi delt reefer]

that would make much more sense

 

[Zakk]

I would have to concur, it sounds like it's not reading the samples right. I've just done 50 tests with that checker, and I will also say that +/- .04 is right too.  I usually run each test 3 times with the same samples, and it can vary each time by about that amount.  The only time I've seen it come up with 0.00 is testing RO/DI water right out of the filter.

 

[Cal_stir]

yes, I calibrate it with the sample I am testing then I add the reagent and hold the button to activate the timer.
I knew something was amiss when I  got it because it gave me the same ppm for 2 completely separate systems, twice.
I bought it online and it wasn't worth the trouble to return it.
I guess I  will have to go back to the visual test kit, in the meantime I will rip this thing apart and see what's inside.

 

[Blob-79]

try using both test tubes. Fill both tubes with tank water, add the reagent to 1 of the tubes, shake for what 3 mins? cant remember off hand. push the button on your checker, wait a sec. it should say add c.1 .put the 2nd tube (with no reagent) in the checker push the button while its checking the calibration with the sample, hold the tube with the reagent in it sidways, tipping it side to side so the air bubble goes back and forth along the length of the tube...and rotate the tube while doing this. This takes all the little air bubbles off the walls of the tube. then take tube 2 out of the checker put the tube with the reagent into the checker. the screen should say add c.2. Press and hold the button untill the 3 minute timer starts. keep the checker sitting vertical sitting on a flat surface during use. When the timer is up it will tell you what the phosphates are at.

The 3 minute timer on the checker is not to be used so you know how long to shake the reagent in. the tube should be in the checker during the 3 minutes.

 

[Cal_stir]

I have done it both ways, if you are too slow it tmes out and turns off, the tube with the reagent is in the checker for the 3 mins, lid closed and on a flat surface, no air bubbles in the tube.
I even watched the hanna video, I am performing the test correctly, I know a heavily stocked, heavily fed 90 gal reef tank, running no macro algae and a 1/2 cup of GFO that is a month old has some phosphates, I also know that no 2 tanks are the same, I just want a reasonable approximation of what it is.
I'm tired of companies building and selling crap that have absolutely no scientific proof that it works except their word.
I think anybody using these checkers should be skeptical of the results, especially if it is zero.
I have already destroyed the checker and thrown it in the trash, I know the titration tests can be a pain to do and the colour charts sometimes difficult to read but they are scientifically proven.

 

[Blob-79]

this is the first ive heard of anyone having an issue with a hanna checker.

The fact that you recieved a defective checker, does not mean that the hanna checkers are unprooven and unreliable.
The hanna checkers work on the same idea of a titration test. The only difference between a hanna checker and a regular test kit is with a hanna checker we dont have to compare with a colour chart. the checker has a led and a sensor inside of it. it can sense minute differences in colour, and is much more reliable then our own eyes.

The hanna checkers are actually lab tests...it isnt a gimmick to get sales from hobbiests

 

[Cal_stir]

After doing more research on reefcentral and other forums I am convinced that they are a gimmic, we all have phophate in our tanks, if we have too much then we will have a microalgae problem, which I do not, I was trying to determine whether my GFO was absorbed out or not, I will let my tank tell me if I have a problem and I will continue with the monthly change of GFO since it is working.
You've gotta be pretty naive to think that there aren't people and companies out there trying to make a buck on every gimmick in the book, especially when there is nothing to verify the result.
I don't think the checker was defective, they just aren't accurate, not even close, just 60 bucks I could have spent on GFO.

 

[Blob-79]

Given that during your testing you were getting numbers that made no sence at all, numbers that ive never gotten with my checker. Tells me that your checker was defective, or there was some sort of error made somewhere. I have tested my checker just as you have, and every reading made sense.

Dont get me wrong..I know there are many companies out there taking advantage of people. I just dont believe hanna checkers are one of them.