I formed my personal opinion after long hours studying the 3 options in threads here on TFF. Since my experience is only with the one of the 3 that I chose and the rest from reading and talking to other people, I would take it with those limitations.
As I see it, there are 3 options that involve CO2 intervention (there is a 4th option called the "Walstad" or NPT (Natural Planted Tank) where you use actual potting soil underneath the substrate but that option is beyond this discussion.) The 3 options are:
1) "Liquid Carbon"
2) "DIY Carbon"
3) "Pressurized"
First of all (sorry if I'm belaboring this) let's be sure we understand the purpose of CO2. CO2 is simply the way a plant gains Carbon, one of the 17 essential nutrients or elements it needs for survival. So Carbon is simply one of 17 "fertilizers" for a plant.
BUT, Carbon is of huge importance to the plant because carbon chains form the flexible backbone of all organic molecules and in particular are used by the plant to create sugars, which are the carriers of energy throughout the plant! Its a lot like Oxygen being carried by blood in many animals. And the CO2 is so important that as a subject it is probably one of four essential "skill sets" for planted tanks (the others being light, macro/micro-nutrients and algae.)
Now that we know its purpose and that its important, why don't we just leave the plant to get CO2 on its own? Well, part of understanding that comes in learning that underwater (fully submerged) plants have access to much less CO2 than above-water plants. In fact, freshwater submerged plants only get 1/4 as much CO2 as emergent (leaves sticking out of the water) plants. And freshwater plants also have it much worse than marine plants because marine plants have adapted to use the high bicarbonate found in salt water as another source of carbon. On top of that, our aquariums are on too small a scale for the type of ecosystem that would "refresh" soil, so if soil is attempted for aquarium plants, it must be refreshed periodically.
That's my quick and dirty prelude to why we're fussing over CO2 so much! Now that we're decided that we're going to help out our plants with some extra Carbon, what are the trade-offs of the common methods? Well, as you might expect, they all have their pros and cons.
"Pressurized" is the accepted "State of the Art" method. It really has no equals. Its simply the best. It can provide controllable, steady amounts of CO2 and do it over long periods without fussy maintenance. But the down side is that its got a very high startup cost, is technically daunting and takes up considerable space, not to mention carrying some danger and risk. Pressurized is more or less required in what we call a "high-tech" setup.
"Liquid Carbon" is the lowliest method of the three. From a practical standpoint one simply buys bottles of a "liquid carbon" product and doses the tank. Technically the chemistry is complicated and this method only came about when biochemists figured out how plants could accept a carbon donating chemical at a different stage in their cycle. The method has at least two downsides: first, its simply not as good as CO2 and doesn't work with all species of plants in the same way. Secondly, its probably even more expensive than pressurized in the long run because the chemical is expensive and you have to do it daily forever.
"DIY Carbon" is the catch-all category for all the methods that try a middle-of-the-road approach. The classic DIY method involves making your own 2 Liter soda bottle system for fermenting sugar and capturing the CO2 in a homemade tube that bubbles into the tank. Commercial variations abound. At first, DIY seems great, but I'm afraid the consensus on TFF (remember I said consensus, not individual stories) is that in the long (or not so long) run, all these systems fall short. The most serious problem is that members find that they are just too much to fuss with, week after week, month after month. They just take a lot of attention. The other problem, more with the commercial variations is that they can cost a lot and keep on costing, just like the Liquid Carbon method. If you discuss these technically with the planted experts I believe you will also find that there are technical difficulties as compared to pressurized.
OK, so where do people fall with these three methods? Well, you can find practioners of all three here on TFF, both pleased and disappointed, probably. For the most part I believe people end up splitting mostly between pressurized and liquid carbon. A very few probably stick with DIY, but most DIY folks are just ones who haven't moved on to one of the others yet. It really ends up being a personal choice about either how serious you are about having a high-tech planted tank (more or less a whole extra hobby in itself, beyond fishkeeping) or whether you are not ready for that yet or find it still too expensive.
Personally I'm a Liquid Carbon practitioner, but that's not for lack of wanting to do both pressurized and Walstad, I'd love to do both and hope to someday.
Oh, and the reason I wrote all this? I don't know the answer to your question
The Nutrafin CO2 systems are one of the commercial implementations of the DIY method I believe (I also group any system that uses little CO2 cartridges into this same group because you just have to keep buying supplies constantly, which is very similar to having to fiddle with the sugar fermentation.)
~~waterdrop~~
