The Planted Tank Forum banner

Co2: Diffuser or Reactor

5K views 37 replies 17 participants last post by  hbosman 
#1 · (Edited)
I'm in the process of getting all the equipment needed to cycle and start my 75 gallon tank. But I'm stumped. What are the advantages and disadvantages of both and what's the better choice? I don't have much experience with co2 at all so all help will be appreciated.

Thanks!
 
#2 ·
A reactor is probably about as efficient as a really good diffuser (basically, an Atomic-style diffuser). A DIY reactor will probably cost about as much as an Atomic. An Atomic (inline or in-tank) is smaller and requires less work to set up. It will fill your tank with micro-bubbles. A reactor requires some thought and a trip to Home Depot, and then some work to put everything together. It will also add another 2 feet or so of head to the canister filter, which will inevitably slow flow a bit. But there are no in-tank bubbles, and if you do it right you'll get 100% CO2 diffusion. An Atomic does require a minimum of 30 psi to function, while a diffuser can be run with a much lower pressure.

P.S. You'll need a canister filter or a powerhead to run a reactor. You don't need either to run an in-tank Atomizer, though you do to run an inline Atomizer.
 
#4 ·
I'm close to ordering the fluval 406 canister filter. I also want to buy a Koralia nano 240 gph powerhead. But I sorta like the idea of the diffuser, it requires less work. Although I might have micro-bubbles I can diffuse those even better with the powerhead.
 
#6 ·
With something as big as a 75g, you may want to use two reactors. There's no possibility of getting a bubble count with a single nv/bc - meaning you'll need a bps of higher than your eyes can count. Which itself doesn't mean you need two lines, but it means you'll have to rely on a drop checker and fish reactions, as well as plant growth and algae over time, to get your needle valve dialed in.

For a general reference, with a JBJ-style bubble counter, I was running 3-4 bps in a 30g tank, with water as the bc solution, using a Grigg reactor, to get a greenish-yellow color on my drop checker.
 
#16 ·
not much if you can minimize 90 degree bends in the plumbing. i have two, one in the reactor itself (i use rex grigg's design) and the other in the spray bar. canisters are closed loops, so vertical head is not much of a factor.

So I see that reactors are the way to go.

But, what are the downfalls with a glass in-tank diffuser?
cleaning it of algae every two weeks.
 
#11 ·
So I see that reactors are the way to go.

But, what are the downfalls with a glass in-tank diffuser?

My other main question is, What is an atomic diffuser? I really don't get what it is.

That would be unbelievable if you could post a video on this sundragon.
 
#14 ·
I use the Carbon Doser external reactor and it's very efficient on larger tanks, hidden under the stand, fully dissolves all the gasses before they can enter the tank, and never needs cleaning, plus I detected no reduced flow.

I think in line or in tank diffusers are fine for smaller tanks and I have never used one so I'm no authority on them but I know if you see bubbles the gas has not dissolved and they need to be cleaned.

This is my opinion on reactors, the simplest model is a RexGrigg reactor, a step up would be the Cerges reactor which is a RG with a wider housing and a center tube, and the ultimate reactor is the Carbon Doser which is a Cerges with foam half way up the center tube and pump to recirculate the water and break up all the gas before it call leave the reactor.
 
#18 · (Edited)
As promised

Here is the video of my inline diffuser :) No "7up" bubbles for me.

Let me know if you have any questions.

Here's a link to my Tank Journal - It's day 2 now.

(Side note) The sparse planting is because more plants are on their way - the LFS are crap for plants and it seem that everywhere online requires a week to process an order to ship you plants Fedex Next day... It's like the 1950s meets 2012, LOL
 
#34 ·
Here is the video of my inline diffuser :) No "7up" bubbles for me.

Let me know if you have any questions.

Here's a link to my Tank Journal - It's day 2 now.

(Side note) The sparse planting is because more plants are on their way - the LFS are crap for plants and it seem that everywhere online requires a week to process an order to ship you plants Fedex Next day... It's like the 1950s meets 2012, LOL
Damn I want your setup. One day maybe, but until then it's plastic pipes for me and regular glass difuser I guess... I might be wasting Co2 but I haven't had to fill my 20 gallon Co2 tank in almost 3 years now lol. I really at least need to get a real aquarium stand....
 
#19 ·
Thank you Sundragon for the video! :)

I've got to say, your tank looks simply amazing for the first stages of the planted part. I really like your scape and the angels.

So does the inline diffuser work as well as a reactor will? - will it also decrease the flow if any.

How many bubbles per second would you think I would need for a 75 gallon?

Another thing I don't really understand is what a pH controller does as compared to a timer like you were using in the video.

What size co2 tank would you recommend? I mean, your only using a 20 oz paintball cylinder. Could I possibly use a paintball tank like yours. I'm actually just getting into paintball so I'd be able to get those pretty easy.

My last question is, How does the atomic diffuser "diffuse" it into your water so quickly?

Thanks man for the help!
 
#20 ·
You're welcome Aquarist14!

Thank you for the compliment - it was about 8-9 hours of straight work!

If you have no bubbles (or leaks) then I think it's safe to say all the CO2 is dissolved so yes. If you have bubbles of CO2 that dissipate into the air, then you are losing some efficiency.

Decrease flow? No, it's a straight shot through with a ceramic liner so nothing gets in the way of the water flow - A reactor may because it's not a straight shot. I don't have experience with those so someone else can give you that information. Honestly, the lily pipe intake is probably a huge reducer of flow because of it's design. The water was instantly clear so I'm not worried.

For the purposes of CO2 injection:
During the day, injecting CO2 causes a drop in pH as it dissolves in the water.
At night, the CO2 is turned off because the plants are using O2 and giving off CO2 - thus the pH would drop even more if the CO2 were to be injected at night. There is also the danger of gassing sensitive fish. Furthermore, pH swings are bad - fish can be stressed by them so people set up their CO2 to turn off when the lights turn off so the pH is more stable and no gassing fish.

The pH controller in conjunction with CO2 injection can accurately control the pH of the tank and it will stop the CO2 if the pH drops too low even during the day. By comparison the timer I have is dumb - it will turn on and off at a preset time.

CO2 tank depends on your situation. Larger = more time between refills, but is heavy and bulky.

For me, paintball tanks are more convenient because I live in the city, I have no car. Renting one to pay $3 to fill my tank is redic... and lugging around a heavy 5-25 lbs CO2 tank is not something I will do :)

I purchased 3 24oz (2lb) CO2 tanks for paintball and I can walk into any sporting goods store that sells paintball and have them refilled. They are portable for those of us who use feet and metro/subways. The larger tank is great if you have a car.

I think that people may be installing the inline diffuser too closer to the exhaust and the bubbles don't have time/distance to dissolve. I gave my system (see the video) an additional space before the Hydor inline heater. I think that distance was enough to allow the CO2 to fully dissolve ~4-5 feet. I can try to measure it if you want. But at 3bps there are no visible bubbles which is what all of us are shooting for.

I think the reactors are great and if I had space and trust in my building skills I'd tackle it. There are some really cool ones that people have built on here.
For me it was an easy choice: $38 for my time, effort involved, and peace of mind.

Let me know if you have any questions about my equipment.
 
#22 ·
I just installed a co2 system with an atomic diffuser. Yes there are the bubbles, I really don't care for that,and how does that effect the fish with all those co2 bubbles everywhere? I'm a newbie with all this stuff and I'm learning, but there is so much information out there that sometimes it's hard to fiqure out just what to do. Jimbo.
 
#25 ·
The bubbles shouldn't affect your fish directly, but you definitely get a drop checker at the least and make sure your CO2 levels are within normal range.

Advice given to me by people who've been doing this much longer:
Get an electronic pH meter that will provide an accurate pH and you can use that along with your KH to get a more accurate estimate of your CO2 levels. There are calculators online that will help with this.

Lastly, agreed - there is a lot online - I met a guy who has 20 tanks at his place and wants to set up his first planted tank and he said he feels like it's his first tank because of all the additional information needed to do it. Do what I do - ask :icon_bigg
 
#23 ·
I've just set up a 75gal with 1 rex style reactor that has been running for a month. When running between 20 and 30 ppm co2 i use around 2 bps with a diy bubble counter. I don't regret the reactor and i haven't noticed much of a difference in flow from my canister filter. I would suggest buying the drop check solution and drop checker and only go to green. For me going lime green is too much co2 and gives my tank a soda pop look with all the bubbles.
 
#35 ·
#37 ·
Thanks for the links! I would sit and stare at the thing spinning - the youtube makes it look like fun!

I looked at the Ista reactor when I was researching CO2 injection. I read that it leaked for some people (not huge, but hard to get it sealed)

I may look at that as an option in the next tank. I just can't have a major leak when living in an 120 year old house :)

I'm honestly surprised that more companies aren't offering reactors that are tested and well built. I mean people pay $$$ for Amano glass.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top