False Reading From Hannah Checker or High PO4

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
I asked this earlier but it was a dead thread. My Hanna checker is reading phosphates at .36 This whole time my PO4 has been reading high I've taken it as a false reading since I've read silicates can cause it to read high and I've been dosing silicates to cause a diatom bloom to compete with dinos. But Today after more reading I found somewhere it will only effect the hannah phosphate checker if silicates are higher then 10ppm. which my salifert kit barley shows 1ppm. Would you think my phosphates did skyrocket somehow or could it in fact be a false reading from the silicates?
 
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
20220629_214214.jpg
 

Muffin87

Active Member
View Badges
Joined
Aug 12, 2019
Messages
454
Reaction score
288
Location
Italy / UK
Rating - 0%
0   0   0
in fact be a false reading from the silicates?
The Hanna PO4 Checker is VERY finicky. Some CRAZY tips:
  1. Take sample water before feeding. Wait for any invisible particles to settle on the bottom of the container, and use a syringe to take a smaller sample from the surface water of the original sample. That's your new sample.
  2. Do not put your fingers inside the reagent pouch. Change its shape from the outside.
  3. It's a TIMED test - PO4 will read higher if you wait too long before starting the test timer. After shaking for 2 minutes, very quickly make sure there are no fingertips on the vial, and start the test timer. This is why the original HI736 has such a short timer that had people often run out of time for the C2.
  4. If you shake too vigoursly, the reaction will happen more quickly. The test being timed, PO4 will read higher. Use an AutoAqua magnetic stirrer to make sure the reagent is mixed with same strength every time.
  5. If you use lanthanum chloride to remove PO4 and the resulting particulate hasn't been removed completely by the mechanical filtration, the reagent will break the bond between the lanthanum and the phosphate, causing the reading to be higher.
  6. Clean the inside of the vial VERY well. As suggested by Hanna, I use their general purpose cleaning solution. Which is really just 0.034% hydrochloric acid in RO/DI. You can make it at home easily.
Just yesterday I tested PO4 in my coral quarantine tank FIVE TIMES. The results:
  • 0.22 (vial wasn't clean probably)
  • 0.06
  • 0.18 (put fingers inside the pouch)
  • 0.02
  • 0.04
I'd totally get a different PO4 test if I wasn't terrible at distinguishing shades of colour.
You'll find plenty of threads saying the Hanna PO4 checker gives inconsistent readings.
 
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
The Hanna PO4 Checker is VERY finicky. Some CRAZY tips:
  1. Take sample water before feeding. Wait for any invisible particles to settle on the bottom of the container, and use a syringe to take a smaller sample from the surface water of the original sample. That's your new sample.
  2. Do not put your fingers inside the reagent pouch. Change its shape from the outside.
  3. It's a TIMED test - PO4 will read higher if you wait too long before starting the test timer. After shaking for 2 minutes, very quickly make sure there are no fingertips on the vial, and start the test timer. This is why the original HI736 has such a short timer that had people often run out of time for the C2.
  4. If you shake too vigoursly, the reaction will happen more quickly. The test being timed, PO4 will read higher. Use an AutoAqua magnetic stirrer to make sure the reagent is mixed with same strength every time.
  5. If you use lanthanum chloride to remove PO4 and the resulting particulate hasn't been removed completely by the mechanical filtration, the reagent will break the bond between the lanthanum and the phosphate, causing the reading to be higher.
  6. Clean the inside of the vial VERY well. As suggested by Hanna, I use their general purpose cleaning solution. Which is really just 0.034% hydrochloric acid in RO/DI. You can make it at home easily.
Just yesterday I tested PO4 in my coral quarantine tank FIVE TIMES. The results:
  • 0.22 (vial wasn't clean probably)
  • 0.06
  • 0.18 (put fingers inside the pouch)
  • 0.02
  • 0.04
I'd totally get a different PO4 test if I wasn't terrible at distinguishing shades of colour.
You'll find plenty of threads saying the Hanna PO4 checker gives inconsistent readings.
Thank you, that's some good info, but I was getting very consistent readings between .03-.05 and am still getting consistent reading just much higher now. last 2 tests were .34 and .36
 

EricR

Valuable Member
View Badges
Joined
Jun 9, 2021
Messages
2,263
Reaction score
2,391
Location
California USA
Rating - 0%
0   0   0
Thank you, that's some good info, but I was getting very consistent readings between .03-.05 and am still getting consistent reading just much higher now. last 2 tests were .34 and .36
That's a pretty massive trend swing. (((0.04ish is what I'd consider happy range vs 0.3x is way high)))

My LFS uses Milwaukee and my Hanna ULR is always roughly 0.02 lower on same sample ((("always" meaning the 3 times I've had LFS test same sample)))
 
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
That's a pretty massive trend swing. (((0.04ish is what I'd consider happy range vs 0.3x is way high)))

My LFS uses Milwaukee and my Hanna ULR is always roughly 0.02 lower on same sample ((("always" meaning the 3 times I've had LFS test same sample)))
I've always found if very accurate, but been running a lot of phosgurd the last few hours tested again and its still increasing two more tests .39 and .4 as of right now
 
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
Mine just did this. I cleaned the vials in some RODI and vinegar and they went back down.
I tested multiple times with different cuvettes and keep the cuvettes clean and filled with rodi water when not being used. Im at a loss with this tank again.
 

gbroadbridge

2500 Club Member
View Badges
Joined
Mar 25, 2021
Messages
3,920
Reaction score
4,059
Location
Sydney, Australia
Rating - 0%
0   0   0
The test is probably accurate, and yes it can rise to that level quickly.
If you test some freshly mixed salt water and get a reading of 0.03 or under I'd say the tester is fine.
 

undermind

Active Member
View Badges
Joined
Oct 17, 2018
Messages
391
Reaction score
554
Rating - 0%
0   0   0
this is my silicate test, i use the hanna checker for p04 i do also have salifert tests but find it very hard to read.
I was confused by this also because the vial is in front of a salifert po4 test.

How long of a time period has passed between being around 0.04 and now where it's testing high?
 
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
I wouldnt say overnight by any means but verry fast. days not weeks. The red circles are me trying to pick a color on the salifert test the rest are from a hanna checker. Before this ive never seen my po4 above .11 but usually sits around .04-.06. But i did stop testing daily on the 17th when i got my first high reading and thought the silicates i was dosing could be causing a false high reading.
Screenshot_20220630-022040_APEX Fusion.jpg
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
This thread discusses interference:

 
OP
OP
D

Davisc1293

Active Member
View Badges
Joined
Sep 16, 2021
Messages
389
Reaction score
100
Location
Rhode Island
Rating - 0%
0   0   0
This thread discusses interference:

Thank you, Looking at that graph and and seeing my salifert test test only showing about 1ppm of si would you trust the hanna checker being almost .4 or would you think the si test is off?
 

Mastering the art of locking and unlocking water pathways: What type of valves do you have on your aquarium plumbing?

  • Ball valves.

    Votes: 50 49.0%
  • Gate valves.

    Votes: 56 54.9%
  • Check valves.

    Votes: 25 24.5%
  • None.

    Votes: 26 25.5%
  • Other.

    Votes: 9 8.8%
Back
Top