Help with math

[SMB]

Am I correct in saying that 1 ppm = 1mg/L?

If that is the case who to believe: Hanna ULR 0.15 ppm or ATI ICP 0.03 mg/L both drawn on the same day.
(The Hanna Phosphate checker has consistent on a weekly basis for 6 months.)

 

[Webslinger]

yes

 

[Skynyrd Fish]

Hanna has a test error range of +- .05 I believe.

 

[Randy Holmes-Farley Verified Community Expert]

Am I correct in saying that 1 ppm = 1mg/L?

If that is the case who to believe: Hanna ULR 0.15 ppm or ATI ICP 0.03 mg/L both drawn on the same day.
(The Hanna Phosphate checker has consistent on a weekly basis for 6 months.)

ICP is usually reported as phosphorus. The kit may be reporting phosphate, which is about 3x higher.

 

[SMB]

ICP is usually reported as phosphorus. The kit may be reporting phosphate, which is about 3x higher.

ATI reports Phosphorus at 11.00 ug/L and Phosphate at 0.03 mg/L
My Hanna Checker is Phosphate ULR ppm

My ATI Nitrate is 2.62 mg/L which is right on my Red Sea Nitrate test kit which I read as 2.

 

[Randy Holmes-Farley Verified Community Expert]

ATI reports Phosphorus at 11.00 ug/L and Phosphate at 0.03 mg/L
My Hanna Checker is Phosphate ULR ppm

My ATI Nitrate is 2.62 mg/L which is right on my Red Sea Nitrate test kit which I read as 2.

Then they disagree. Not especially unusual, but I know it is frustrating.

 

[biom]

ICP is more accurate than hobby grade colorimetric tests. If talking about Hanna checker mine (phosphorus ULR) would give different readings if I’m using different batch of powder reagents but it was years ago, I hope now they perform better.

 

[SMB]

Then they disagree. Not especially unusual, but I know it is frustrating.

Randy Holmes-Farley


Yup. One I might add a phosphate remover the other I would leave alone.

 

[Randy Holmes-Farley Verified Community Expert]

I'd leave it alone. Worse to be too low than a little high.

 

[Miller535]

ICP is more accurate than hobby grade colorimetric tests. If talking about Hanna checker mine (phosphorus ULR) would give different readings if I’m using different batch of powder reagents but it was years ago, I hope now they perform better.

Yep. I'd trust ICP over hanna any day.

There are many things that can throw a the ULR off. For instance that particular checker is suppose to be rinsed immediately after use with RODI water only not tap, even though I think most use tap. Keeping the vile clean of finger prints is also of utmost importance. As @biom said, could be your powder reagents. Fish of hex posted a video about that a while back. And how he learned to always compare a current batch of reagent with a new batch. Also important that you get all the powder out and shake it for the full two mins before testing.

 

[SMB]

Pretty good about testing protocol, use a stop watch etc.
It could be the reagent but this same batch was giving me readings of 0.06-0.08.
The RS 425XL has been very stable for over a year. Never had a real ugly phase or algae but the tank was set up with 3 year old rock from another of my tanks.
In the last three months have had a bloom of bubble algae and it was time for an ICP check as I get them about 3-4 times a year.
So was trying to decide if I wanted to run some GFO in a reactor.

 

[Randy Holmes-Farley Verified Community Expert]

So was trying to decide if I wanted to run some GFO in a reactor.

With ATI telling you 0.03 ppm phosphate, I would not.

 

[SMB]

With ATI telling you 0.03 ppm phosphate, I would not.

Thanks
Will keep up with my usual weekly WC
And manually control the bubble algae