Hanna phosphorous checker issue?

VanDalsenReef · Feb 15, 2022

So odd thing here. Tested my phosphorus twice. First time was 38 and the second was 23. That's a larger difference than what I was hoping. Could it be that the first vial was too scratched up or too much "particles" in the vial

moz71 · Feb 15, 2022

Could very well be! Measures in parts per BILLION! There is a lot of factors that could impact that small of a difference in a hobby grade test kit.

VanDalsenReef · Feb 15, 2022

moz71 said:
Could very well be! Measures in parts per BILLION! There is a lot of factors that could impact that small of a difference in a hobby grade test kit.

The second time I used a new vial and took water from the sump where there isn't as many particles.

Randy Holmes-Farley · Feb 15, 2022

VanDalsenReef said:
The second time I used a new vial and took water from the sump where there isn't as many particles.

If you used the Hanna ULR HI736, it has a 10 ppb range of error, so that result is barely outside of it.

VanDalsenReef · Feb 15, 2022

Randy Holmes-Farley said:
If you used the Hanna ULR HI736, it has a 10 ppb range of error, so that result is barely outside of it.

Would it be good to test again to get an "average"

Randy Holmes-Farley · Feb 15, 2022

Both values seem OK to a tad on the high side, so I'm not sure I'd worry about the difference too much..

VanDalsenReef · Feb 15, 2022

Randy Holmes-Farley said:
Both values seem OK to a tad on the high side, so I'm not sure I'd worry about the difference too much..

The nitrates were sitting around 5 so I wanted to either drop the po4 or raise no 3

Randy Holmes-Farley · Feb 15, 2022

VanDalsenReef said:
The nitrates were sitting around 5 so I wanted to either drop the po4 or raise no 3

Because someone told you about the Redfield ratio?

Forget that. It is not ever better to worry about ratios than to focus on the absolute numbers. Ask whoever told you why a ratio matters more than the absolute values. If one is high (or low) does that mean that it's best to make both high or low? Why not make both optimal?

I recommend 0.02 to 0.1 ppm phosphate and 2-10 ppm nitrate.

VanDalsenReef · Feb 15, 2022

Randy Holmes-Farley said:
Because someone told you about the Redfield ratio?

Forget that. It is not ever better to worry about ratios than to focus on the absolute numbers. Ask whoever told you why a ratio matters more than the absolute values. If one is high (or low) does that mean that it's best to make both high or low? Why not make both optimal?

I recommend 0.02 to 0.1 ppm phosphate and 2-10 ppm nitrate.

Kind of but more trying to do a 100/1 ratio. So the same as you. Thank you for all the info