Cheap probes for common ions and parameters?

Ghost25 · 07/08/2016, 12:25 PM

I would like to monitor as many parameters as possible electronically rather than relying on colorimetric assays. Hanna has a number of handheld checkers that test phosphate, calcium, alkalinity, nitrite, etc. Each unit is about $50, surely each of these is just a relatively simple probe with some basic signal processing and an LCD.

Has anyone been able to locate these probes OEM or Chinese knockoffs of them? I tried Alibaba and eBay but had little luck. I'm sure if the Chinese made these probes alone they could be had for $10-$15 each.

EDIT: Just realizing that the Hanna checkers are actually colorimeters...

Does anyone have experience with UV-Vis spectroscopic methods for detecting compounds of interest? They're probably not optically active.

WLachnit · 08/13/2016, 04:10 PM

Well....unfortunately, colorimetric methods typically employ a specific reaction that will change a chromophore's optical properties. The alternative of an absorbable measurement (using a molar extinction coefficient) typically requires a relatively pure sample. So, ion selective probes are the best bet, but they tend to drift over time and need to be recalibrated on a regular basis.

Ghost25 · 08/13/2016, 08:26 PM

Yeah, now that I've had my tank running for a while I've come to realize that the parameters I would really want to measure are temperature, salinity, carbonate hardness, and maybe nitrates.

Unfortunately determining carbonate hardness is difficult though it is possible. Nitrate can probably be measured by ISE.

07/08/2016, 12:25 PM	#1
Ghost25 Registered Member Join Date: May 2016 Posts: 143	Cheap probes for common ions and parameters? I would like to monitor as many parameters as possible electronically rather than relying on colorimetric assays. Hanna has a number of handheld checkers that test phosphate, calcium, alkalinity, nitrite, etc. Each unit is about $50, surely each of these is just a relatively simple probe with some basic signal processing and an LCD. Has anyone been able to locate these probes OEM or Chinese knockoffs of them? I tried Alibaba and eBay but had little luck. I'm sure if the Chinese made these probes alone they could be had for $10-$15 each. EDIT: Just realizing that the Hanna checkers are actually colorimeters... Does anyone have experience with UV-Vis spectroscopic methods for detecting compounds of interest? They're probably not optically active. Last edited by Ghost25; 07/08/2016 at 12:42 PM.

08/13/2016, 04:10 PM	#2
WLachnit Registered Member Join Date: Feb 2008 Location: Bay Area, CA Posts: 1,722	Well....unfortunately, colorimetric methods typically employ a specific reaction that will change a chromophore's optical properties. The alternative of an absorbable measurement (using a molar extinction coefficient) typically requires a relatively pure sample. So, ion selective probes are the best bet, but they tend to drift over time and need to be recalibrated on a regular basis. __________________ (1) 300g mixed reef (Starfire DT) + 100g Sump (2) 100g Softie tank (Starfire DT) My Build Thread: http://www.reefcentral.com/forums/showthread.php?t=263472 Last edited by WLachnit; 08/13/2016 at 04:34 PM.

08/13/2016, 08:26 PM	#3
Ghost25 Registered Member Join Date: May 2016 Posts: 143	Yeah, now that I've had my tank running for a while I've come to realize that the parameters I would really want to measure are temperature, salinity, carbonate hardness, and maybe nitrates. Unfortunately determining carbonate hardness is difficult though it is possible. Nitrate can probably be measured by ISE.