AquaticTechTank.net

Hmm, 366/24 =15.25
So my tank really has 15 ppmw of co2. This low value makes sense since my 30k sensor broke, I'm using the 10k. I'm getting black beard algae as a result and the plants hardly pearl. The fish are happy though. My only concern is the fish's health and behavior when the sensor reads 16K+ppmv.

I've taken the co2 controller offline and have been doing it the old fashion way for the past few weeks.


Sent from my iPad using Tapatalk HD

I was researching aquatic CO2 field measurements and noticed this thread. I noticed your screename from TPT. I didn't realize you had your own forum. I skimmed through this thread and thought you may find one of the articles I came across useful;
They are essentially doing exactly what you have done. They reference the exact hardware, PTFE, design and function. They compare this method to other academic research methods. It may answer some of the question you have had.

I should have made the casing out of glass, since silicone bonds to it better than acrylic, hence the leak problem.

I found a diy under water CO2 sensor much like what Zorfox linked but it uses arduino type constructions. It's more in-depth and detailed. It was has a temperature & humidity sensor which is smart. If the humidity is high, we know we have a leak?

http://www.mbari.org/education/internsh ... ategui.pdf
Cost is around $500-$600, the most expensive being the Teflon AF (amorphous fluoroplastic resin) tube at $300 at biogeneral.com. I'm assuming the teflon tube you buy on ebay for $5 is not the same stuff.
The teflon can be found here as well
http://www.sigmaaldrich.com/catalog/pro ... &region=US


I'll add an attachment in case this link no longer works

I thought I'd give the CO2 sensor another try. This time, build the casing as water tight as I can and as cheaply as I can. Thanks goodness the CO2 sensor wasn't permanently damaged. I just had to calibrate it using CO2meter's software.


2" pvc plug with cord grip


Inside I had to thin the top off with a router.


Trap adapter for the silicone membrane.


The adapter has a washer inside which I used with the membrane and silicone for safety measure.


The hardware: Arduino, CO2 senseAir K-30 10%, 5v fan, DHT-22 humidity & temperature sensor.
The fan is for circulation, and the humidity sensor is to alert me if it's too high or if a possible leak. The membrane is porous enough for H2O molecule to pass through. If the humidity is too high, I can remove the plug.




The fit was too snug and the board broke in half so I kept it.


Final product. I'm out of the CO2 game but I'll set up a yeast reactor in a bucket to test. I'll send the data to a mysql database online. I'll post the result soon.

So here's the result of the logs



I added a 1 liter yeast diffused it a piece of chopstick and circulated with a powerhead in a 5 gallon bucket. I stopped at 60ppmw. It was recording every 7 seconds so I changed the code to record every 10 minutes instead.

CO2 is still climbing. It's at 100ppmw at last check. I pulled out the CO2 to see it tapered out. Who knew DIY CO2 can go that high. I guess it'll keep climbing if nothing consumes it or diffuse it out of the water. I guess shutting off CO2 at night is a good idea.