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Estimating CO2 injection rates in ml per minute

If we assume CO2 is a simple gas we can apply Henry’s law but there seems to be more to it..! :nailbiting:
says..
http://www.thuisexperimenteren.nl/infopages/Carbondioxide in water equilibrium.doc
Above is a .doc version you need M$ word.. Google cache version click here.

According to this the atmospheric Carbon dioxide in water equilibrium is

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I'd like to add something to this conversation but I have nothing. Me, this discussion and my education parted company about seven post back. :rolleyes::D However, problem I find with this level of accuracy and being dead on balls accurate (that's technical term for the scientists amongst you) is it's something that can never be replicated or a one size fits all result. A bit like E.I dosing the results might be right for your tank an nobody else's. Water temp, surface agitation, water chemistry,amount of plants, type of lights, reliability of co2 equipment, throughput of filter, dirty diffuser the list is endless and that's just in your tank so how would it relate to someone else's? If you found out a result today could you replicate it tomorrow? Maybe some water evaporated off in an open top tank and you have more surface agitation than you had yesterday, it's like herding cats, the possibilities are endless.

Coming back to the OP original question. Why can't we use those things we see in hospitals that measures the amount of gas going through a tube? That's something I've often wondered. Another thing I did one night while drinking a decent bottle of Merlot :rolleyes: and I'm probably going to wish I never said this...I had a bubble counter that was running too fast to count the bubbles so what I did was download an app for my phone that you could import in video and edit it. Then you could look at the video in the timeline at the bottom and play it back frame by frame and see how long it took in 1/10's of seconds per bubble. Obviously this won't tell you how much gas went in because of the size of the bubble but it can give you an idea of if you're fine tuning your own bubble count...I guess.

In my situation though it was never stable enough which was probably down to the quality of the regulator. Even whether the heating was on in the house seemed to make a difference.

BTW I was asked to "leave" school when I was 14 so I'm just glad I made it this far in the conversation :)
 
I guess the point for me is just understanding whats the level of co2 in water, when in equilibrium with the atmosphere.

I do not need it to have good results, it was more of a curiosity. A 1 point pH drop works for a lot of people. For me I kind of need 1.4 to 1.5, to get optimal results.

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Yeah, for sure. I have an inquisitive mind as well. I'd like to know the results even if they are no use to me. I suspect one day they will. When I tried dropping my ph by one point I found there appeared to be a bit of a glass ceiling around .8 of a drop. Didn't seem to matter what I did it wouldn't go any lower.

My water comes out the tap at a PH of about 7.2, after the water change which pretty much re-set the gasses before co2 on my PH was about 7.0 and I took ph tests with a calibrated pen every half hour. At lights on I was at about 6.4 so I gave the needle valve an 1/8th of a turn and left it hoping to get some more results the next day and confirm the turn had worked.
The next day before the co2 was on and with a calibrated pen the ph was at 6.8 so I guess not all the co2 had gassed off from the previous day. By the time the lights came on I measured a ph of 6.2, the DC wasn't yellow and my Ember Tetras were showing signs of discomfort, hanging around in a group in the the top corner breathing heavy so I immediately dropped the water level and let the lilly pipe break the surface and turned the co2 back down an 1/8th of a turn.

I left it like that for a few week, DC was green at lights on, fish were happy and no signs of co2 related plant issues. Then the quandary starts with is it my ph pen, is it my calibration fluid, is it my DC fluid,is it me :D

The moral of this story is the 1 drop in PH relates to 30ppm of dissolved co2, maybe I had it maybe I didn't. But someone forget to tell the fish and plants and they're the best judge of how much co2 should be in a tank IMO.
 
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A 1 point pH drop works for a lot of people.

0.5 pH drop can work as suficient, at least it does for me.. :) It kinda depends, i guess for the biggest part with the light intensity and plant sp. you are growing. I don't want to know the amount of co2 many people are wasting on their 30ppm or 1 unit pH drop goal. Without knowing they could have same results with much less.
 
I don't want to know the amount of co2 many people are wasting on their 30ppm or 1 unit pH drop goal. Without knowing they could have same results with much less.

Well, while I understand your perspective, I come from the high tech side, and testing upper/lower requirements comes pretty soon.

I guess a lot of people could use less, specially when you have a very "relaxed" relationship with your tank.

For me, it is all about learning how it works and why it works. More light? Less light? More co2? Less ferts? More water changes? I'm trying lots of things so I can learn it.

I would be glad to use less CO2, but in my case it has to be there to keep up with 150+ PAR of light. You have to know your tank, understand its boundaries.

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I would be glad to use less CO2, but in my case it has to be there to keep up with 150+ PAR of light. You have to know your tank, understand its boundaries.

I think there lies the problem. One person's experiment doesn't really relate to someone else's tank. It's quite overwhelming the amount of information available and everyone who frequents this forum are here for very different reasons. If I see a new comer in the forum one of the first things to ask is what are they trying to achieve. Some people here just want some plants growing, some are getting a scape put together ready for a photo shoot for competition, some just a community fish tank and other don't want any chemicals or gas and high lighting just want it as nature intended, the Walsted way.

To the unsuspecting new punter they might feel that they have to replicate the competition tanks habits to grow some plants and before long their pockets are empty and they are disillusioned with the hobby and worse not even enjoying something that should be an enjoyable experience. The 1 unit drop is more for the quick scaper and right on the edge for people with fish of being a disaster IMO. BTW that tank of yours is beautiful. :clap: I can only dream. I can't see any fish in there though so I can only guess which side of the coin you are on. Going off some of the chemical/mathematical hieroglyphics you posted earlier you're clearly a man of science.

I'm not being negative at all about this whole thing BTW. I'm following the post with interest because I will glean some useful information out of here and would like to see the results. I often find myself carrying out experiments just out of curiosity, the problem being when I do and let people know I often find that something else negates the results which I'd over looked but hey, it was fun while I was doing it.

My point was that if we all do the funnel thing capturing co2 we input and post our results what do we do with the answer? For instance right off the bat not all that co2 is going to end up in the container because some will dissolve in the water before it gets to the container so we have a duff result already. It's akin to finding out how long a piece of string actually is then realising we don't know what to do with the string or why we wanted a piece of string to start with.

I learnt my lesson from a shrimp tank on my desk. I would sit with test kits reading every post available. Stressing over every parameter and looking for answers, measuring this and measuring that. I've even seen myself nip home from work because I forgot to dose my macros in the morning. :D The shrimp tank, I put some cat litter in from a previous set up, few cuttings from my home tank, some RCS and a couple of stones I found round my way and the pleasure I got out of it was immeasurable. Only dosing when it looked like it needed it and changed water when I had some spare time.

The 1PH drop on a tank like yours is probably a must. On my desk shrimp tank not necessary and again, someone forgot to tell the plants because I was sick of thinning them out.
 
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