Drop Checkers and Target CO2

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Larry,

You are absolutely correct. However, for me, half (or maybe 1/3?) of the fun of this hobby is turning my aquarium into a limnology/data collection study. Rather than using EI, I built a database that I use in conjunction with my myriad of test kits to track my water quality variables. Even though it is not useful for the purpose of growing better plants, I attempt to hit points rather than ranges, I guess because I am sick in the head. :)
 
Larry,

...for me, half (or maybe 1/3?) of the fun of this hobby is turning my aquarium into a limnology/data collection study... I guess because I am sick in the head. :)

We would be great friends. I like the way you think! And your quick - not sick - in the head. The only rules that should govern our hobbies are the ones that we impose upon them.
 
elwaine said:
Next question: Is there a difference in plant growth if one gauges the levels of CO2 as being between 25 - 45 ppm vs 30 - 35 ppm?
I'm not really sure, but have guesses. For example, the 30ppm CO2 rule of thumb number came from a bunch of folks playing with what is now known as a (sometimes) unreliable measurement (the assumptions made in the KH/pH/CO2 formula) and breaking the old rule of 15-20ppm CO2, which such reliable sources as the APD and Krib (many of the same gurus who post today) used as the long standing benchmark. Wouldn't it be neat to find out with (hopefully) more accurate numbers, even in an amateur/hobbyist experiment with relatively cheap equipment and a little bit of time? :)

It just seems counter intuitive to use gross "Dump and Bump" fert schemes (aka, EI) - to avoid rate limiting values from developing - and then focus on tightening up CO2 dosing in order to achieve better plant growth. Anyone happy with EI should be happy with a single bubble drop checker with a 4 dKH solution and run their CO2 at a bubble count rate that turns the color in the bubble yellow green (not green). That way, CO2 would be closer to 45 ppm than 25 ppm and would not be rate limiting.
Yes, and this is EI wonderfully stated. But its easy to think of many questions spawned when one has a better guess about CO2:

If we can force green plants red via stressing them by limiting the second biggest macro nutrient (the low N brings reds method), what happens when we play with the biggest macro? (Also note lots of folks who use EI do it while setting maximum limits to control growth, or based on anecdotal experience, or whatever other reason.)

What if the amount of avaiable CO2 in a tank actually changes throughout the day in a way we can see, but currently can't because of the wide limits available to a hobbyist's most accurate measurement device (drop checkers). If I did set a 30-35ppm CO2 range, would I stay there all day, even in a presurized setup, or would I see my CO2 much higher in the day and night (lower uptake periods during the photoperiod)? Do I really only need that target as my minimum limit? Or are those periods even higher uptake at all? Will I even know since it takes so long for the gas to equalize?

How much CO2 am I pushing into a sunlit tank I feel good about on CO2 when I got there using the old "see algae or poor plants? Increase CO2. See fish gasping? Thats bad... lower CO2. Wait, need more CO2..." method?

*shrug* Dunno yet...

Thank you for your time and thoughts and expertise!
 
FYI, for those out there, I made up a bunch of 4dKH solution today... selling the remainder on EBAY for next to nothing.

cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320329616880

Will do some work to here soon to figure out what I am going to make my other reference solution. My second drop checker should be here later in the week.
 
czcz - Excellent questions! Once I get the hang of what I'm trying to do by following the recipes of those who've succeeded long before I began this hobby, I just may want to tackle some of the questions you raised.
 
And the dKH of the indicator solution is...???

Just now thought of something. All the reading I did on the bubble checker said to add enough indicator (Bromothymol blue, in my case) to turn the liquid a nice bright, easy to see, green. So that's what I did. I took about 8 cc of my known dKH 4 clear solution and added 3 or 4 drops (can't recall which) of Bromothymol blue... until the color was an easy to see bright green.

So what is the dKH of Bromothymol blue? If it's not 4 - and somehow I doubt that we could get that lucky - than the true dKH of the liquid inside my bubble will not be 4 after adding the indicator to the standard dKH 4 solution. Furthermore, the more drops of Bromothymol blue that one adds, the further away from 4 it will be. How does that effect the 25 - 40 ppm CO2 range? Will it result in a left or a right shift in that range?

My head is beginning to hurt - gotta stop thinking about this.
 
I hope that doesn't matter enough to really matter and is in our margin of error of our scales/existing measurement devices. Its supposed to be 20 drops per mL, yeah? So:

8mL @ 4dKH.
.2mL/4 drops @ (assuming its a reagent in DI) 0dKH.
= 8.2mL @ 3.902 dKH
 
Of course! You are absolutely correct. Hey... if I was smart enough to do math, I would have been a physicist instead of a physician.
 
Heh. I just look for excuses to operate with my pocket calculator.


(I really just look for opportunities to post this video for fellow nerds who, like me, were not aware of it until recently.)
 
Gotta respect Kraftwerk. Really it is amazing how much these guys actually influenced a lot of newer bands/acts.
 
Well my second drop checker got here today. Took me a minute to figure out how to fill it (physics was kicking my butt), but I put it in the tank with a 4dKH solution. Going skiing up in Vail CO tomorrow, but when I get back next week, I will mix up some ~6dKH based on czcz's calculator and put this to the test. Kind of excited about it :)
 
Slick. I still haven't ordered mine :( I'll go do that now... will follow up in a week or so, yeah, unless you've got new input? Thanks!
 
czcz, unfortunately, the second drop checker got demoted (or promoted?) to the nano cube garden, so I have to order ANOTHER drop checker for the 29G. I do fully intend on trying this out though... efforts have just been focused on the new tank for the past week or so.
 
Just curious: do you guys actually find yourself adjusting CO2 (or does the drop checker change color) that much after setup/a couple weeks in? With the watch for gasping fish and algae/poor growth method, I have adjusted maybe once a month as plant mass increased or I saw algae. I figured I'd only use the drop checker(s) when wondering what was going on or for a couple days every couple weeks as a sanity check?

Does the drop checker change color during the photo period? Is it "too much" or "too little"? When (ballpark) during the photoperiod?

Thanks.
 
With 4dKH solution in the checker, mine definitely changed color during the photo period. It started out on the high end, and would go back to green as the day wore on. Of course, now I am using a pH controller, so this is no longer an issue - it is always green. But - that's part of the reason I want to get a second checker - it will allow me to double check and narrow in on a very tight range of CO2. Probably not necessary, but you know me, the more information I have at my disposal the better I like it :).
 
My drop checker finally arrived today. Shipping from hong Kong sure takes a while. haha. It took a lot of finegaling to actually get the 4dkh solution into the bulb part, but I managed.
 
Yeah, I find the best method is to use an eye dropper and try n squeeze it into the ball. Kind of pain to get it in there...
 
hmm, well it looks like my levels are too low. The color is pretty much a blue-green and I believe it was supposed to be a slight yellow green? I set it up about 5 hours ago, so I imagine it would have reached equilibrium by now
 
Yup, I would say you are low. Right in the sweet spot with 4dKH is about 30ppm CO2 and it will be a bright green color. It will turn more yellowish when you get on the high end.
 
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