Not Tom, but as I understand it (I may be wrong-please comment), this "Co2 probe" is something to be used like a PAR meter-for spot testing. It probably can't be left in the tank permanently because the membrane will clog up, but I expect it will last days if not weeks before the membrane gets clogged.
Last week I ordered a 12"x12" sheet of .003" thick membrane, it was $42 with shipping. I hope the reaction time is quick enough to be useful. Here is their detailed data sheet:
[attachment=1061:name]
I have a new Lamotte KH tesk kit (results are in ppm's-more accurate I think than degrees) and just ordered a new PH probe for my Milwakee ph tester.
I plan to use prepared drop checker fluid-not for the color but because it will (hopefully) be 4dkh. I expect the Lamotte test kit to bear this out and will double check my testing skills. Also, since it is a prepared solution, it could be used as a control of sorts for things discussed below.
I plan to put about 5ml of drop checker solution in about a 3" X 3" piece of membrane and wrap it around the bottom of the probe. It seems to me that in order to get the fastest reaction, we want to have the largest amount of membrane surface with the least amount of liquid.
Then using the KH/PH calculators/chart I expect to resolve to Co2.
I am also going to make a sealed 5ml bag using the membrane and tie it up next to a drop checker using the same solution. Then watch to see how long the colors match-this will give me an idea of how long it takes for the membrane to clog up.
It will be interesting to see if the membrane can be cleaned by rubbing it with fingers, running water or it is is a one-time use and then shot.
This Co2 thing is driving me nuts because I don't have the experienced eye to know what I am seeing. At least with this I hope to know what ballpark the Co2 is at a give spot. I also want to know the differences in the dispersion between the Co2 outlet, the corners and especially in the sump. Shouldn't the sump be a good average Co2?
I think it will also be interesting to measure the rate of drop in PH with different amounts of flow.
Anyway, I feel like a monkey with a banana inside a mayonaise jar-but hopefully there is some experience or knowledge to be gained here--wisdom is not free.
Here is a lengthy discussion on the subject:
http://www.plantedtank.net/forums/diy/171111-converting-ph-meter-co2-meter-more.html
Ideas, corrections or suggestions appreciated.
