IO Rodeo Colorimeter

As part of the population that suffers from some level of color blindness I find myself suitably agitated by the color based test kits.

So one day as I sat staring at a tube and a color chart trying to place it by process of elimination. I decided there had to be a better way.

This lead to google, which got me to colorimeters, which got me to really big price tags, which got me to eBay, to older hach models, to high reactant prices ( compared to API kit ).

Disappointed I back tracked a few steps and eventually stumbled upon an old kickstarter project for an educational colorimeter that uses a pc And adrunio to do the grunt work.

The project was funded more the a year ago, so I figured they were all gone. But low and behold they are still selling them on there website.

http://www.iorodeo.com/colorimeter

searching there site, they actually have calibration curves for the API test kit. That sold me along with the $110 price.

It can't be less accurate then my eyes and even if I only use it a few times, it'll still make a beat thing to own.

Anyway it's on order, I should get it in the next few days. Will have to post again with results.

Ps.
I found the nitrite curve ending at 2ppm weird so I asked and got this as an answer.


In my experience with this test, absorbance starts to become non-linear above 2 ppm nitrite and above 3 ppm, the line is almost flat. This means that there is no color change between 3-5 ppm. You could read up to 3 ppm, but to be on the cautious side I just have the calibration up to 2 ppm as this is reliably linear.
I have been collaborating with an aquaponics expert (which I am not) and when we were developing this calibration he thought up to 2 ppm would be fine. However, once you have started using it I would love your feedback.



This actually makes me feel more confident this will work.

Time will reveal all, but anyone else here use/used this?



Sent from my iPhone using MonsterAquariaNetwork app

So its here and assembled
Assembly was easy, and the thing its made from what looks like 1/8" black acrylic.
It came in these 2 awesome reusable plastic locking boxes.
Sadly, the assembled thing does NOT fit back in the box, but its oooo so close.. maybe i'll take the saw to it to make it fit..

Here it is assembled.



Once it was up and running and the Arduino programed i setup my first test with it.
Here is the API color tubes.


And the solutions moved into the curvets.


And the numbers the colorimeter says, i clicked the test button a few times each to see how it would vary w/o changing anything.


The only one i'm really iff'y on is the Nitrate number..
I have no idea of thats right.
I'd says is anywhere between 5ppm color block and before the 40ppm bock on the color chart.
So i guess 10ppm is in that range..


If i run it with no solution, or just clear tank water. it always says 0 or 0.01.
So thats good at least..

Guess i'll have to see how it moves over the days/weeks

Huh.. the Ammonia in the pic looks horrible. its no where near that dark in real life..

All right before i continue one some points of intrest.

As i've been playing with this device, i've come the conclusion i'll need to find some ind of case for the Adruino board.
Right now its just sitting on a plastic box which would be non conductions but it's going to need something better in time.


the 2nd things is how i'v been measuring out the 5 mills of water for the API kit.
I found out long ago that the surface tension of water makes filling the vial a pain the butt.
So i shopped around, and found this at Walgreens for $5.

It actually supposed to be for dispensing accurate dosages for baby meds.
But i fine it works great for filling the tube exactly the same each time.
You twist the top part and it sets the depth of the plunger to one of 2.5, 5, 7.5 or 10 mills.
Then its just dip it in the tank, draw water, and then push it out into the tube.

So after the last test round, it was time for a water change.
I pulled out my buckets and filled one with 5 gallons from the tap then added some Tetra AquaSafe Plus.

Well the chemicals did there work, i pulled 5 gallons from the tank.

I then took a sample of the TAP water and developed it.
I figured what i'd see would be 0's across the board.
And thats more or less what i got..


Ammonia and Nitrite are clearly 0 on both the color chart and the colorimeter.
The Nitrate is also basically 0 on both, but not to the level i was expecting to see.

Why the elevated levels on Nitrate in the Tap water?
It is the colorimeter off by 2.xx?
Is that really in my tap water?
Is the granularity of the API test just not accurate that far and subject to error?

So i dug up my city water testing results from 2012.


According to that Nitrate was at 0.53 ppm at the time of test.
It also says that fertilizer, animal wast, or sewage can cause the level it go up.
So, to me that says:
1) The public system can't completely eradicate nitrate.
2) The delivery system is subject to some level of contamination.

Regardless of which one, i'm willing to say that the massive amount of rain we've had as of late may well be the cause of a micro spike in the tap water.

Don't know what to think about the 2.5x reading.. its odd, but not enough to really make me question the colorimeter.

After the water change i went and had dinner.
This gave the tank filter time to mix in the new water.

I did the tests again..


Based on the Pre water change number and the number in the tap water itself i would say the Nitrate drop here is real enough to be accurate.

Before this next part i want to state the tank HAS NO FISH IN IT.
It only has 3 24" stalks of Lucky Bamboo.

So after the Post Water Change tests were done i added 5 mills of Grocery store ammonia to the tank.
This will be the 2nd week cycling the tank like this i think, so i'm expecting this to convert fairly rapidly at this point.

After letting the tank sit for 1 hour to let the filter mix the water up.
I did the tests again.
( i'm starting to sound like a broken record )



Ammonia levels went up!
Haza! an expected result!

Nitrate also went up as well..
Hum.. i did give it an hour.
Don't think the cycle would work that fast.

I'm not even going to guess at that micro of a change though.

We'll see how things look in 14 hours or so.