Hanna PO4 vs. ICP

[Groovyg]

Long story short - tank has some gha. Hanna phosphorous checker was reading 8 (converted to 0.024 PO4). Sent in an ICP and received it back with a phosphorus reading over 100 and PO4 over 0.3. Borrowed a friends phosphorous checker and both are reading exactly the same thing. Still 8. Originally it read high so I started some gfo.

I am aware that some PO4 can be bound in the GHA. But would this mean a different reading on the ICP and Hanna checkers? Wouldn't it be the same in the water either way?

The GHA is not better and looks to be getting worse. I also have some cyano on the sand now.

NO3 15
Alk 8.3
Mag 1450
Cal 450
Tank is an IM40 running a small skimmer (9004) and floss.

I want to get rid of the GHA, but if I don't know my PO4 levels, I'm not sure how to proceed. I have plenty of CUC.

are you dosing any bacteria?

 

[Bubblebass]

are you dosing any bacteria?

I have been carbon dosing but no bacteria.

 

[Uncle99]

Long story short - tank has some gha. Hanna phosphorous checker was reading 8 (converted to 0.024 PO4). Sent in an ICP and received it back with a phosphorus reading over 100 and PO4 over 0.3. Borrowed a friends phosphorous checker and both are reading exactly the same thing. Still 8. Originally it read high so I started some gfo.

I am aware that some PO4 can be bound in the GHA. But would this mean a different reading on the ICP and Hanna checkers? Wouldn't it be the same in the water either way?

The GHA is not better and looks to be getting worse. I also have some cyano on the sand now.

NO3 15
Alk 8.3
Mag 1450
Cal 450
Tank is an IM40 running a small skimmer (9004) and floss.

I want to get rid of the GHA, but if I don't know my PO4 levels, I'm not sure how to proceed. I have plenty of CUC.

Phosphate, whatever the level, is likely on the higher end but is not the only contributor to GHA, light, especially certain spectrums and intensity in combination with a nutrient source brings the green stuff.
Whites and reds it loves.
I trust my Hanna.

 

[Bubblebass]

Phosphate, whatever the level, is likely on the higher end but is not the only contributor to GHA, light, especially certain spectrums and intensity in combination with a nutrient source brings the green stuff.
Whites and reds it loves.
I trust my Hanna.

My single AI prime is turned down to assist. Red and green have always been at zero.
UV 70
Violet 70
Royal 53
Blue 53
green 0
red 0
White 12