Dissolved CO2 or CO2 bubbles - what's better?

[Art]

Some experienced hobbyists believe that it is better to force CO2 into solution as close to 100% as possible. It then gets circulated throughout the aquarium for plants to grab.

Others believe that it is better to have CO2 bubbles blasted all over the aquarium as these bubbles are pure CO2 and provide plants with easier access to pure CO2 as opposed to CO2 in the viscous liquid we call water.

What's your opinion one way or the other? What reactor are you using?

 

[GreggZ]

Some experienced hobbyists believe that it is better to force CO2 into solution as close to 100% as possible. It then gets circulated throughout the aquarium for plants to grab.

Others believe that it is better to have CO2 bubbles blasted all over the aquarium as these bubbles are pure CO2 and provide plants with easier access to pure CO2 as opposed to CO2 in the viscous liquid we call water.

What's your opinion one way or the other? What reactor are you using?

To me doesn't matter much which is truly better. If there is a difference I'm guessing it's shades of gray.

For me it's all about the soda pop fizz look. Some may love it, but for me it's a deal killer, so 100% dissolution for me.

That being said would be curious to see what others say.

Anyone done both and seen any meaningful difference??

 

[Art]

To me doesn't matter much which is truly better. If there is a difference I'm guessing it's shades of gray.

For me it's all about the soda pop fizz look. Some may love it, but for me it's a deal killer, so 100% dissolution for me.

That being said would be curious to see what others say.

Anyone done both and seen any meaningful difference??

I remember @plantbrain had a thread going on one of the sites about seeing better growth and pearling with the CO2 bubbles. I think it was tied to his Venturi design reactor.

 

[BigWave]

Think this more involves people who hate the CO2 Soda stream look in their tank where it looks like a cup of Sprite. It takes quite a bit of time and effort to 100% dissolve CO2 into water.

 

[DDio]

Think this more involves people who hate the CO2 Soda stream look in their tank where it looks like a cup of Sprite. It takes quite a bit of time and effort to 100% dissolve CO2 into water.

If you fully dissolve CO2, the opposite happens and you wind up with a bunch of O2 bubbles from the plants pearling

When I set my tank up I was rubbing my hands together like Mr Burns thinking I was going to have crystal clear water, free from those pesky CO2 bubbles and then the pearling started and I had just as many bubbles in the tank lol.

 

[DDio]

I think a reactor does a much better job of being efficient with your use of CO2, as long as you're controlling it with a controller. I'm at about 6 months on a 10lbs tank in a 120 gallon and while it does seem like it's very close to empty, it's still running.

 

[JPog]

Yeah, I think it's purely preference, I don't think one is better than the other. Look at @Cheattha Sae-Teaw tank. The Dutch winner/TOTM and he uses a small in-tank diffuser on his 5 footer. Most always default to a reactor for a tank that size.

As far as pearling I never did a controlled test comparing methods, but my setup with an in-tank diffuser, pearls more than the one with an in-line one. I think there's some confusion on pearling itself. Many people feel pearling is the result of the water being o2 saturated. I don't think that is true. Pearling to me (I can be proven wrong) is the result of the plant photosynthesizing so fast that the o2 being produced can't be absorbed fast enough into the water. Think of when you cut a stem (that isn't pearling), the plant "bleeds" o2 because it comes out at a fast and uncontrolled rate. The water didn't suddenly become o2 saturated from the one cut stem. This to me is similar to pearling. The o2 is being released to quickly to be absorbed.

 

[Freshflora]

Yeah, I think it's purely preference, I don't think one is better than the other. Look at @Cheattha Sae-Teaw tank. The Dutch winner/TOTM and he uses a small in-tank diffuser on his 5 footer. Most always default to a reactor for a tank that size.

As far as pearling I never did a controlled test comparing methods, but my setup with an in-tank diffuser, pearls more than the one with an in-line one. I think there's some confusion on pearling itself. Many people feel pearling is the result of the water being o2 saturated. I don't think that is true. Pearling to me (I can be proven wrong) is the result of the plant photosynthesizing so fast that the o2 being produced can't be absorbed fast enough into the water. Think of when you cut a stem (that isn't pearling), the plant "bleeds" o2 because it comes out at a fast and uncontrolled rate. The water didn't suddenly become o2 saturated from the one cut stem. This to me is similar to pearling. The o2 is being released to quickly to be absorbed.

Something that I think would support your theory is that you can have fish gasp at the surface despite a tank pearling like crazy. If a tank‘s pearling was just the result of the water column becoming O2 saturated, I don’t think gaseous exchange and proper surface agitation would be as important as it is.

 

[Art]

I think a reactor does a much better job of being efficient with your use of CO2, as long as you're controlling it with a controller. I'm at about 6 months on a 10lbs tank in a 120 gallon and while it does seem like it's very close to empty, it's still running.

Dom - can you explain how you're controlling it?

 

[DDio]

Dom - can you explain how you're controlling it?

Currently with a Milwaukee controller, but I've been considering trying to update my old Apex controller, buying a probe, and then using that so that I can get some logging data, along with a few other benefits to using it.

 

[Art]

So, appreciate everyone's comments here.

Let's distinguish pearling from the CO2 bubble spray. Yes, both are bubbles and they both can look like Seven-Up/Sprite in the aquarium.

It has been posited that CO2 bubble spray is "better" for plants than full diffusion into the water. The reason is that the CO2 bubbles bring pure CO2 to the plant and it's easier for the plant to uptake it. This, in turn, means that plant would theoretically grow faster than if it had to "pull" the dissolved CO2 from the water (30 ppm).

I think it's valid to ask whether "faster" means anything if your plants are going fine. If it doesn't matter to you, then not having the CO2 spray bubbles may not be optimal because them plus the natural pearling will cause a real Seven-Up effect.

Not sure I've I'm explaining it correctly.

 

[Art]

Currently with a Milwaukee controller, but I've been considering trying to update my old Apex controller, buying a probe, and then using that so that I can get some logging data, along with a few other benefits to using it.

I use an Apex and love the logging. Also gives you many controller options that function as a redundant backup if things fail.

 

[DDio]

I use an Apex and love the logging. Also gives you many controller options that function as a redundant backup if things fail.

Yep, had two Apex's at one point, one controlling two reef tanks. Sold one off but had the other running about 10 years. I didn't really see the need to use it on this tank until recently. With the HVAC on and no whole home humidifier installed, my house is at 20-30% RH during the winter so I didn't really know how much evaporation there'd be and holy smokes is there a lot lol. I have an Avast Marine ATO and you can only use it with an Apex since it is specifically for use with the Apex. I'd love to hook that up to address some of this evaporation versus messing with my python. But the data logging, controlling the solenoid, monitoring PH swings overnight, and controlling the heater would be excellent benefits. I'm just hoping I'll be able to update the firmware since it's so old. The last time I updated it was 2014 or so.

 

[Art]

Woohoo, that is an older one. Hope you can update the firmware.

A controller offers just so much. Many benefits.

 

[ryancamaratta]

I have one tank with in-tank, one tank with in-line, and starting one now with a reactor.
Pros for in-tank:
- easily controllable flow of CO2, you can mess with your outflow, powerheads, etc.
- alot of the designs for in-tank diffusers are really pretty nice, yeah I don't like having equipment in the tank but a lot of them are so aesthetic that it's like an elegant decoration in the tank.
Cons for in-tank:
- more equipment to be cleaned and yanked in and out!

Pros for in-line:
- better dissolution vs in-tank
- less equipment in-tank
Cons for in-line:
- do I have to list it lol? The 7 up effect. I fall in the "not a huge fan" category
- not much versatility. The CO2 is only going one way lol. It's going out your output

I'll just talk about reactor because I'm just starting with one. Not having 7up will be nice, and it's the most efficient dissolution method which is also really nice.

I also love not having equipment in the tank so another win, albeit with the caveat that a reactor is a pretty big separate piece of equipment that needs its own cleaning and maintenance schedule too.

You could argue that it carries the same con as the in-line, that flow direction isn't adjustable, but honestly with the near perfect dissolution rate from a reactor I'd argue that it's a moot point for reactors, it doesn't matter where the flow is pointed when the water column is perfectly CO2 saturated.

 

[GreggZ]

You could argue that it carries the same con as the in-line, that flow direction isn't adjustable, but honestly with the near perfect dissolution rate from a reactor I'd argue that it's a moot point for reactors, it doesn't matter where the flow is pointed when the water column is perfectly CO2 saturated.

+1. When the water column is saturated the direction of flow means little. I have done tests taking the pH readings in all different parts of tank and it's the same everywhere.

I liken it to the same thing that would happen if you put a couple of drops of food coloring in your tank. After a minute or two it's evenly distributed. Same thing with ferts, once it's dissolved the reading is the same everywhere. In my experience it's the same with a CO2 reactor.