LaMotte SMART 2 Colorimeter accurate for phosphates?
- Thread starter falconut
- Start date
HighlandReefer
Team RC
FWIW, the Smart 2 Colorimeter provides no better detection limits and accuracy than does the Hach PO-19 low end phosphate kit, which sells for around $90.00. Refills are cheap. The same applies to the other phosphate meters. The Hach Model PO-24 runs a little more then the PO-19 
Community Clean Water Institute
Volunteer Water Quality Monitoring Program
Sampling and Analysis Methods
http://www.ccwi.org/issues/analysismethodsccwi07-4.pdf
From it:
Phosphate-Phosphorus
1. Color wheel
By Hach Total Phosphate Test Kit Model PO-24 Catalog 2250-01 using the Low Range
procedure. The observed value from the disk is divided by 50 to obtain the mg/L phosphate
then divided again by 3 to represent the mg/L PO4-P.
Community Clean Water Institute, Citizen Monitoring Program www.ccwi.org Updated 4/12/2007 5
The color wheel part number 24898-00 is from 0 to 50 mg/L in unit divisions. For the Low
Range method this represents a 0.02 to 1 mg/L phosphate range or 0.007 to 0.33 mg/L PO4-
P. The reporting limit for this method is the first non zero division at 0.007 mg/L PO4-P.
For the medium range method the reporting limit is five time the Low Range method at 0.03
mg/L PO4-P.
2. Colorimetric
By LaMotte’s Smart 2 Colorimeter with the reagent kit code: 3653-SC. This is an Ascorbic Acid reduction method. The colorimeter measures the amount of color in the sample. This sample absorbance is compared to a calibration curve stored within the meter to return a concentration of phosphate in mg/L. The calibration curve is set by LaMotte. The phosphate
result provided by the instrument is divided by three to present the phosphate-phosphorus value (PO4-P). The reporting limit for this method will be the same as the color wheel at 0.03 mg/L PO4-P.
Community Clean Water Institute
Volunteer Water Quality Monitoring Program
Sampling and Analysis Methods
http://www.ccwi.org/issues/analysismethodsccwi07-4.pdf
From it:
Phosphate-Phosphorus
1. Color wheel
By Hach Total Phosphate Test Kit Model PO-24 Catalog 2250-01 using the Low Range
procedure. The observed value from the disk is divided by 50 to obtain the mg/L phosphate
then divided again by 3 to represent the mg/L PO4-P.
Community Clean Water Institute, Citizen Monitoring Program www.ccwi.org Updated 4/12/2007 5
The color wheel part number 24898-00 is from 0 to 50 mg/L in unit divisions. For the Low
Range method this represents a 0.02 to 1 mg/L phosphate range or 0.007 to 0.33 mg/L PO4-
P. The reporting limit for this method is the first non zero division at 0.007 mg/L PO4-P.
For the medium range method the reporting limit is five time the Low Range method at 0.03
mg/L PO4-P.
2. Colorimetric
By LaMotte’s Smart 2 Colorimeter with the reagent kit code: 3653-SC. This is an Ascorbic Acid reduction method. The colorimeter measures the amount of color in the sample. This sample absorbance is compared to a calibration curve stored within the meter to return a concentration of phosphate in mg/L. The calibration curve is set by LaMotte. The phosphate
result provided by the instrument is divided by three to present the phosphate-phosphorus value (PO4-P). The reporting limit for this method will be the same as the color wheel at 0.03 mg/L PO4-P.
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Also, the HI 736 Ultra Low Range phosphate meter looks to be pretty good, although I haven't had any personal experience with it, yet.
I couldn't find the accuracy claims for the LaMotte equipment, but I'm skeptical about its accuracy at the lower levels we see in most tanks. Their equipment is designed for other applications, really.
I couldn't find the accuracy claims for the LaMotte equipment, but I'm skeptical about its accuracy at the lower levels we see in most tanks. Their equipment is designed for other applications, really.
