Electronic PH, ammonia sensors.

[Mr. Ninja]

Has anyone found the like, or had anyexperience with them? (I don't know of any)

It would be nice to get some sensors in a system that were reusable. (if I ever get to building a system :? )

[badflash]

For our purposes you are better off with test kits. The meters are expensive and fussy. You need calibration solutions, and they are a general pain.

Once you are established, you will use your eyes and nose.

[Mr. Ninja]

Ok, thanks. But I was thinking more in the range of one that just gives off a certain voltage, to make a diy version.(and to maybe incorporate it into an automated monitering system, so if I left I could check up on it.)

So, different PHs smell different? :P You learn something new every day...

[badflash]

A healthy system smells good.

[alex281]

i agree, even with the better priced accurate meters, they arent really necessary, i know its time to buffer because the water becomes extremely murky. asides from the usual test youll be doing, things change rather slowly in ap and by the time they do you will have full realization of whats going on using nothing more than your eyes and nose.

[dead_sled]

Ok, thanks. But I was thinking more in the range of one that just gives off a certain voltage, to make a diy version.(and to maybe incorporate it into an automated monitering system, so if I left I could check up on it.)


If you are electronically inclined and able to do some programming, there are diy options available. They are some Arduino based ph sensors. I am sure there are other micro-processor based ph sensors that you can do as well. Search it up. :ugeek:

[jackalope]

I'm kinda partial to the test kits

Just my 2 centavos .......

[Mr. Ninja]

dead_sled: Thanks, it didn't occur to me to prep-end 'arduino' to the Google search.


The reason I want to do this is to be able to remotely moniter the system, as we are often away.


(e.g. be able to access it from a web server)

[David - WI]

The Neptune Apex can monitor dozens or hundreds of sensors including pH, temperature, DO, etc but from what I've seen ammonia, nitrate, nitrite, etc are either chemical/color tests where you have to take a sample, add a reagent, and look at the color or use a color meter - or fairly "exotic" monitoring systems:


Continuous monitoring of ammonia in water and wastewater streams is becoming increasingly important for plant operations and process control. Unfortunately, on-line ammonia monitors are generally very expensive, complex, and labor intensive instruments. Most are automated versions of ammonia selective ion electrodes methods better suited to laboratory measurements. Others are automated colorimetric devices or instrumental methods that are difficult to justify on a cost basis. http://www.analyticaltechnology.com/public/product.aspx?ProductID=1048

The hard part (I think) about using something like the Arduino is getting the calibration and isolation of the sensor worked out in order to get accurate/repeatable readings... not the calculating or transmitting the results.

[FancyDress]

You need calibration solutions, and they are a general pain.

[Billy Boy]

This is a subject on which I have done a lot of research, but I have little hands on experience so far.

Generally, it is pretty easy to measure ph and electrical conductivity with low cost electronics. DO is more expensive. The electrical conductivity will tell you in aggregate how many ions you have in solution but it won't tell you how much of any particular ion... ie NH4+, NO3-, NO2-, or for that matter, K+, or P3-.

So far, the best technology that I have been able to find that does that directly are semi-permeable membrane sensors. Basically they are a membrane that sorts out just the ion you are looking for, and then does a electrical conductivity test on the solution you get. Last time I checked, they were expensive (>$500per), short lived (<3 months in continuous use), finicky (require constant recalibration), but available from Honeywell. For some reason I'm not able to track them down right now on Google though?

I concluded that there was basically nothing out there that does the job very well, and even less that is remotely affordable.

But, I have an idea that might help solve that?

The idea is basically to run an automated system that draws off a fixed volume of water fro you system, and then adds the correct number of drop of reagent to the sample. Then it shines light through it, and reads the color with a simple spectrometer like one of these...

http://publiclab.org/wiki/spectrometer

Depending on how many reagents you had you could automatedly test for basically anything you wanted. and it would be pretty cheap and durable.

But it is not a product you can purchase and would require some work to get going.