Phosphate: Redsea vs Hanna

[Trevorreilly73]

Hi reefers, I recently got a Hanna ulr phosphate checker. Originally I was using Redsea phosphate test.

On the Redsea test I get no colour change whatsoever.. leading me to believe I have no phosphate.

Using the hanna checker I have 0.27ppm phosphate.. leading me to believe I have way too much.

Has anyone any experience/advise on this?

 

[Randy Holmes-Farley Verified Community Expert]

If you use both on new salt water, what do you get?

 

[Trevorreilly73]

If you use both on new salt water, what do you

If you use both on new salt water, what do you get?

A great question, one I never thought of myself. What is the purpose to testing a batch of freshly mixed saltwater? Contamination coming through the rodi system?

 

[Randy Holmes-Farley Verified Community Expert]

A great question, one I never thought of myself. What is the purpose to testing a batch of freshly mixed saltwater? Contamination coming through the rodi system?

It’s mostly to test the test itself, but it can also point to an ro/di problem.

 

[hsp]

I have a HI774 and noticed weird changes in my tank. So, I did 3 tests in rapid succession using exactly the same methodology as per instructions and got the following results:

0.12ppm

0.06ppm

0.08ppm

I shared this with Hanna support and was told:

Have you considered the following:

• Are there any scratches/marks on the vials? You may need to purchase new vials
• Are you ensuring there are no finger marks or that the vial is wiped dry properly?
• Have you verified using the calibration check set i.e. HI774-11?
• Have you done 3 tests of the same sample taken? The accuracy of the checker is ±0.02 ppm ± 5% of reading.

Failing all the above attempts, you may have to purchase a new replacement as the HI774 checker is out of warranty.

I think in my case some scratches on the vials caused the issue.

 

[Randy Holmes-Farley Verified Community Expert]

Yes, orientation of cuvettes is very important if they have any defects.

 

[Dburr1014]

Hi reefers, I recently got a Hanna ulr phosphate checker. Originally I was using Redsea phosphate test.

On the Redsea test I get no colour change whatsoever.. leading me to believe I have no phosphate.

Using the hanna checker I have 0.27ppm phosphate.. leading me to believe I have way too much.

Has anyone any experience/advise on this?

I could never get a good reading with redsea either.
Hanna is they way to go if you can.