Horizontal CO2 Reactor - Yugang 鱼缸 Reactor

[JayP]

Sorry, new as well, just checking my math here...

My tank is a 60p, so 60x30x36cm. So my surface area would be, in inches, 24x12" = 288. So then my Reactor Surface Area would be about 16 for the 1.5ph drop, or 8 for the 1.2ph drop.

It just seems quite small, to do potentially an 8" long 2" diameter tube. Would my filter's flow (biomaster 250, set to like 50% flow power) be too much?

Your math is correct, and yes, for tanks this size, the reactors will be small. For example The reactor I built (pictured below) for my 25g (60X40) is 3.5"X6". This is why I personally wouldn't bother to build a reactor for anything less than 20g, although, some have built in-tank reactors for smaller aquariums and there are threads here describing those.

Here's where you run into an issue though, the smaller diameter the tube, the more turbulent your flow will be, regardless of how you turn it down, because you can only turn it down so much before you have too little flow in the tank and thus poor CO2 circulation around the tank and not enough surface agitation for off-gassing. I first tested a 2" diameter pipe on the 25g and it was quite noisy. I recommend at least 3.5 " diameter, but again, the shorter length causes turbulence, just not as bad. This is where I am now, because of the fast turbulent flow through the short reactor, it's terribly inefficient. That's where the bypass comes in. Direct most of the flow around the reactor to give CO2 and water more time in the reactor to interact.

I also recommend designing a reactor with the input centered on one end but the output offset on the other. This way you can design the reactor a little larger than necessary and just rotate it to turn it down. If doing this place your CO2 input in an area of the input end that stays in the top quarter of the reactor regardless of where you have the output rotated to. This can help reduce CO2 bubble sounds if your tank is in a room you want to keep things quiet.

Reactor on my 49g tank.


Reactor on my 25g tank. It's mounted to the bottom of the stand top so this photo is taken by me lying on my back.

 

[SmartAlec13]

Ah okay, so it sounds like it may not be worth digging into since my aquarium is pretty small by comparison (16-17gal).

 

[Koan]

Would my filter's flow (biomaster 250, set to like 50% flow power) be too much?

Probably not, but you have the option to build one and try it, or build one with a bypass and a ball valve,



and tune the flow that way

 

[Koan]

it may not be worth digging into since my aquarium is pretty small by comparison (16-17gal)

Using a Yugang reactor has two benefits:

• it removes fizzy bubbles from your tank if they bother you, and
• has the ability to put a ceiling on your CO2 injection, so if you have a less than top-end needle valve you can still be sure your injection will stay consistent and below whatever maximum you set.

If you want one of these benefits for a small tank, Yugang also did an Open Flow reactor he calls a Spray Bar. It goes inside your tank, but it works for little tanks

@*Ci* made a gorgeous one here:

Post in thread 'CO2 Spray Bar - a summary'

Dec 28, 2024

I finally got one of my Co2 spraybars assembled and installed. In some private correspondence with @Yugang, he determined that my “68g with a 40”x 17” surface area = 438.709 mm2 surface area. Divided by 17.7 gives 24.785 mm2 for the CO2 Spray Bar. If we would use a 1 inch diameter tube, we would need it to be 976 mm long to have that surface area.
This calculation is for about 1.5 pH drop. What we know is that 0.3 pH drop corresponds to a factor of 2 in CO2 ppm, therefore for an estimated 1.2 pH drop we could do with 976/2 = 488 length of the 1 inch tube.”

To simplify:

For a 1.5 pH...

• *Ci*

• 
• 
• 

If neither of these apply, there's always an inline diffuser. I use this diffuser on my little tanks,




It's in-line, but really it's a sideways version of a standard in-tank diffuser. The water goes past the diffuser disk, and your flow is not obstructed

 

[xNitroPT]

Probably not, but you have the option to build one and try it, or build one with a bypass and a ball valve

Can anyone explain why the valve must go on the bypass? Or is it specific to the design shown. If bypass was above, I assume valve would go on reactor side? I just think about the fluid dynamics of it and, if you were to fill it slowly, the head (height) is exactly the same between the two so in theory it’s 50/50 split between water flow. So if we want to slow down the reactor flow, why not have the valve on the reactor line to begin with? You’re essentially controlling 50-100% of your flow to go through reactor, rather than controlling 0-50% of flow going through reactor. Is my thought process wrong here?

 

[hamfist]

Can anyone explain why the valve must go on the bypass? Or is it specific to the design shown. If bypass was above, I assume valve would go on reactor side? I just think about the fluid dynamics of it and, if you were to fill it slowly, the head (height) is exactly the same between the two so in theory it’s 50/50 split between water flow. So if we want to slow down the reactor flow, why not have the valve on the reactor line to begin with? You’re essentially controlling 50-100% of your flow to go through reactor, rather than controlling 0-50% of flow going through reactor. Is my thought process wrong here?

It doesn't have to go on the bypass. I have my valve on the reactor part of the circuit for the very reasons you state.

 

[apper]

Hello I'd like to build a horizontal reactor for my aquarium. The aquarium is 150cm x 60cm x 60cm. From what I've read here, the reactor length should be about 51cm (150x60/17.7). However, I'm not sure what diameter pipe I should use. Will a 5cm pipe be sufficient?

 

[xNitroPT]

Hello I'd like to build a horizontal reactor for my aquarium. The aquarium is 150cm x 60cm x 60cm. From what I've read here, the reactor length should be about 51cm (150x60/17.7). However, I'm not sure what diameter pipe I should use. Will a 5cm pipe be sufficient?

So you did (150x60/17.7) which is right. That gives you 508.

Your length times diameter should equal this number. 51cm x 5cm is only 255, not 508. You would need a 10cm diameter pipe if you use 51cm length.

For your tank you can use any pipe that has length x diameter = 508

 

[Naturescapes_Rocco]

Hello I'd like to build a horizontal reactor for my aquarium. The aquarium is 150cm x 60cm x 60cm. From what I've read here, the reactor length should be about 51cm (150x60/17.7). However, I'm not sure what diameter pipe I should use. Will a 5cm pipe be sufficient?

Check out my journal 1 and journal 2, both of which are 150x60x60cm and use an ARC Acrylic horizontal reactor!

The dimensions of this reactor are 65cm long by 10cm diameter. At this size, they were pretty overpowered at full strength for a 150x60x60cm tank -- so having an offset exit for the water so you can rotate your reactor to adjust the power was really nice. It's far better to oversize and be able to reduce the power, than to under-power it!

 

[JacksonL]

Having recently upgraded my filter from a Fluval 307 to a Biomaster 850, I need to change my reactor setup to handle the extra flow when I switch them over.
Currently I have a Cerges reactor that I made with the smaller 10” housing. Considering I already get some bubbles making their way into the tank in the afternoons with the 10”, I figure I need to upgrade and install a bypass.
I found an absolute bargain on Amazon, a 20” clear filter housing delivered for $22.
Can anyone help me with whether it would be worth setting this up as a horizontal reactor?
The tank is 135L, with a 80cm x 40cm (32”x40”) footprint, so my understanding is the housing will be far larger than I need if horizontal.
What would be the benefits to running it horizontally considering it is oversized for the tank anyway?