Preferred phosphate test?

imchris

New member
I've been checking my phosphate with an API test kit and always measures zero. I took some water to my LFS and they came up with .11. From my readings, .05 seems to be the high limit of where I should be. I need to be able to test this more accurately. What is the preferred tool for checking this? I've seen a lot of people post about a Hanna but I don't know which is the best. There seems to be several models. Any help would be appreciated. Thanks!
 

Pittsburgh

New member
Hanna makes only one phosphate checker - Low range 713. I use it and like it.

There is also Hanna phosphorous checker. It's suppose to be ultra low and it measures phosphorous, you would need to convert it to a phosphate reading.

For my SPS tank I'm perfectly happy with my 713.
 

tigrtraps

New member
The low range 713 measures ppm

The Hannah phosphorous measures ppb. If the reading says 11 you take it times 3.066/1000. Which gives a reading of .033ppm Phosphate. I'm told the phosphorous meter is more accurate especially at these very low ranges due to the sensitivity.
 

alexander_ktn

New member
I use the high sensitivity phosphate test from Merck and am very happy. It's a manual test, so you have to compare the color to a color scale, which introduces some additional uncertainty/possible user error.

What I've heard the digital Milwaukee low range phoshate test should also be quite accurate but more expensive than the Hannah one.
 

mess7777

New member
API is [profanity] for phosphates. It shows 0 and the next step is .25....so that range is way too big for a reef tank. I have a hanna now and although it isn't perfect(getting all the reagent into the vial can be challenging), it is a good tester in my opinion. At least you don't have to compare to a colour gradient that looks all the same after you stare at it too long!
 
Last edited by a moderator:

imchris

New member
Thanks for the help guys! For those using the 713, have you done any testing on the vials themselves? I read where some people set up 1 vial with the test solution and the other with the tank water. I may not be describing this correctly but I know they were utilizing both vials. Then some others commented that this may be a bad idea due to inconsistencies in the vials themselves. Has anyone done any testing to confirm or dismiss this?
 

alexander_ktn

New member
You could run 2 tests, 1 per vial, with the same water and see how high the difference is. I think we are talking amounts that are well below the accuracy of the test itself.
 

tigrtraps

New member
The 2 vial thing is cause the Hannah checker has stupid auto off times. After you calibrate the test you have to put in the powder and shake it up, in only 2 minutes. So you have to have everything laid out before hand, not waste too much time pouring the powder, and shake it appropriately in the time given.

Some people use 2 vials so they can have everything ready. Put the first one in, calibrate with that one, then put the 2nd one in premixed with powder/regent/stuff and test. The issue is the Hannah checker has been calibrated for the first vial and it's glass. THIS IS ONLY WHAT I'VE READ ON HERE. I have not a single clue if it's true.
 

a.browning

New member
I used to have the HI 713, but upgraded to the 736. I like the increased precision, and with an sps tank this is a must. You will see a lot of varying opinions on Hanna, bottom line is, if you're very precise with the test, then you will get accurate results. I've always read to use the same glass vial for step one and two--minute differences between the vials can skew your reading. The old meters timed out after 2 minutes, which plenty of time, but just know this ahead of time so you don't waste reagents. The new meters time out in 3 minutes so you have even more time.

Basically, you put in the vial, press the button. As soon as it says add C2, start a timer for 3 minutes (so you know how long you have till time out), have the reagent packet pre-cut/open, pour it in and swirl it until all is dissolved. Usually only takes a minute or so. I would not advise to shake vigorously as this creates a ton of microbubbles, which can be a pain to get off the vial. Make sure no microbubbles are on the sides of the vial when you put it back in, or else you'll mess up results. I know it sounds like a lot of instructions, but it's really not that bad.
 
Top