Tom,
I after reading through the thread none of it made much sense and there didn't seem to be any conclusive evidence or study except that adding Ca did work for Jay.
I have Pogostemon stellatus and it has no signs of Co2 deficiency (if that's what we are saying is the likely cause), which I recently trim before the pic. in the 1st post.
This pic shows it behind the blyxa much bigger yesterday when I trimmed it.
If you share your method of measure Co2 accurately I'll attempt to measure mine. My regulator is on a Milwaukee controller being diffused in a MD1000 reactor. I don't trust my needle valve enough to run without the controller as sometime the bubble rates appear to change, but once the PH target is met it turns off with whatever Co2 still in the reactor still diffusing.
So you are saying the drop checker has a +/- of 10ppm Co2 discrepancy? Which would imply that with 4dk solution 30ppm expected target I can be at 20-40ppm instead.
BTW this plant didn't do well when there wasn't much of a plant mass either it's not like it was added after the tank was established. (just for the record)
the problem is you tradxe off KHJ accuracy for loss of pH accuracy with the drop checker.
You also really lose a lot of the response time.
Drop checkers(DC's), have about 2 hour delay, many have trouble treading the colors, you have 3 basically, yellow, green and blue, not much in between.
Plants make a good indicator of something "Right"
You can EASILY rule out an issue with Ca++ by simply seeing if someone has low Ca++ and no such issues, or ask someone to confirm if your hypothesis is true or not. If you have stunting already.......then you cannot do the test, you have some dependency already and it's likely CO2.
It;s only when the plants are growing well and with folks that can lower/add Ca++.
Then they can test and see, since with nice good growth, they have a reference control.
They can test that specific issue and if they get no response, they cannot say why the plant is that way in your case, but they can say why it is NOT.
I've had CO2 issues stop adding gas. Stunted smaller tips growth was common. P stellata got monsterous prior. Same with the other psecies listed.
I've gone through this maybe 5-6 times, all with the same result and conclusion. I tried all sorts of ratios and chemicals, I was never once able to induce stunting. So have other folks.
I have had CO2 issues, and then got these same exact stunting patterns.
I have also reduced the light intensity, which also lowers CO2 demand, and such issues have gone away as well.
Good quality CO2 equipment, a good vernier caliper handle ona Swagelok or even better, an Ideal needle valve with the same handle type, a good in line check valve with MPT or FPT 1/8" threaded fittings post solenoid (get a good solenoid as well, Burket's etc) Nice dual stage regulator etc.
Go high grade there with CO2, low intensity but wide good spread and high quality light.
I think many just go a little too cheap with CO2, and often assume too much about their measurements of CO2. I wish I had an easy solution for everyone.
However, I really do not for accuracty measurements. Some are very $$$, or very imprecise. Depends on the types of alkalinity in your tap water. If it really was all bicarbonate for everyone, that would be the pH/Kh chart pretty good. Most measure KH only once in a great while when something is very wrong typically, few measure it often.
You could do it without all RO and then add bicarb as your only source of alkalinity, that should be pretty accurate in a very well mixed system depending on WHERE you place the pH probe.
Think about it this way, you calibrate the pH probe correct?
You can calibrate and confirm a test kit say for NO3 by making a known stock solution and measuring that over the desired range(say a 5 ppm and 20ppm solution of NO3)
So.......how might you do this for a CO2 measurement and get say a 10ppm and 40ppm standard solution of CO2?
Not so easy.......
O2 is easier and more used, reliable etc, but not CO2 so much.
I measure both, but they instruments I use are several thousands of dollars. Yes, I wanted to know that bad. :hitting:
So, then I have this nice techy stuff, I still have to figure out a calibration method. So I got some known %gas and made sealed bubbling chambers and pH probes with known KH reference cells.
So it's gotten a long way from simple hobby level stuff.
Still, the CO2 meter has been calibrated and the results are very different from what folks expect.
I've also used a similar approach at the same time with O2 meters, using the Hach LDO meter methods. I also data log CO2 over the 24 hour period as well as O2.
This way we can get a complete picture.
I do not like to assume I know more than I do, but at some point you have to stop cutting bait and fish.
More next post.
Regards,
Tom Barr
. If you can measure all 3 things collectively well, then you can understand a lot more.
