Co2 equipment.

[Fish are friends]

I'm looking at setting up a nano show tank where the aquascape will be the main feature not the livestock. I want to possibly add co2 but am clueless so need an idiots guide on equipment needed, which brands to avoid etc. I've seen some regulators on Amazon for £39. How would they compare to the £70 ones. It's a 55l tank so I'm guessing a 2kg for extinguisher would last forever. The lighting is a nicrew plant 24/7 but I can't find any specs on that and I won't use all of its functions and will buy a second of needed. (Not new to planted tanks just co2)

 

[Wills]

Good that you are prepared for the fire extinguisher- for the regulator I would go for a Co2 art one they are expensive but they are the thing not to risk. If you can’t do Co2 art make sure it’s a dual stage regulator so you can control how much comes out of our cylinder and how much goes to your bubble counter. Not familiar with the light unit but you want to be aiming for between 1 watt per litre and 0.5 watt per litre. Your water quality and fertiliser will really determine success with this I have really high nitrate in my water so moving to RO. You just have to keep light, Co2 and ferts in balance which is difficult but the thing to focus on.

 

[Colin_T]

Small tanks and carbon dioxide (CO2) don't always go well together. A small volume of water can quickly become saturated with CO2 and you kill everything in it.

Do you really need CO2 on a small tank?
Perhaps set the tank up without adding CO2 and see how it does. There is plenty of CO2 in the water from the filter bacteria and fish, as well as in the atmosphere. Most plants really don't need more of it.

How many rivers, ponds and lakes have supplemental CO2?
The plants grow well in these areas without people pumping any CO2 into the water.

 

[chkltcow]

In the past month since I got into this, I bought one of the "fire extinguisher" types as well as one of the "two bottle DIY" types. I'm planning on making a video reviewing them this weekend, but my advice is to go with the 2 bottle DIY stuff like this: https://www.amazon.com/dp/B08HPZN43R/?tag=ff0d01-20

I'll give you my reasoning and a writeup on it when I get home

 

[chkltcow]

Alright, so.... here's the long version if it.

Fire extinguisher style
I got an Fzone 2.5l CO2 generator from Amazon a few weeks ago: https://www.amazon.com/dp/B07YCPKBV3/?tag=ff0d01-20 It's based on a fire extinguisher with a regulator and needle valve that screws onto it. It's decent, but twice the price of the other one I listed. It comes with everything you need in the kit, though (check valve, diffuser, hose, etc) where the one I linked above does not. You have to provide the diffuser, some air hose, and a check valve.
Pros:

• Looks good. Looks REAL good.
• Everything included
• Easy to fill, easy to clean
• It's a pressure vessel I trust, unlike 2L drink bottles

Cons:

• Not exactly cheap
• The needle valve is really fiddly. Could just be my particular one that's a problem though
• You lose CO2 during the filling process. A LOT of it if you don't act fast

So let's talk about that last one. You dump in your Citric Acid dry. You dump in your baking soda on top of it dry. Then you add 300ml, and as soon as it hits them, the clock is started. The reaction is going and you're producing CO2. Until you can get that regulator screwed on, it's just gone. The reaction will fizzle itself out in a few minutes to hours, but it builds the pressure inside the body of it that will feed your tank for several weeks, based on how much you're letting out the needle valve. My first fill lasted around 2 weeks.

2 drink bottle style
I bought the much cheaper "2 drink bottle" kit from Amazon to use on my 20G planted tank. It's $30 on Amazon right now. It's not much to look at, the bubble counter body is thick and cheap feeling plastic, and the instructions are in the worst "Chinglish" I think I've ever seen. But... the thing works and it works well. The instructions are clear enough that I could tell how to put it together and how to load it up. I did pay a little extra to get the one with the solenoid, but that's only because it was in stock and I'm impatient and didn't want to wait another week for the one without. It'll prove to be useful once I put it on a timer anyway. But I'd say $30 is the price point you're probably looking at.

Pros:

• Less than half the price of the fire extinguisher style
• Doesn't produce CO2 until pressure drops and more Citric Acid runs in, so it could be opened (if you had some reason to) without losing ALL your CO2
• Gives you an excuse to enjoy a couple bottles of soda!

Cons:

• It's ugly. Hide it
• Didn't come with diffuser or check valve. Figure those into cost calculation

Ultimately this is the one I'd recommend to anyone who wants to do a cheap CO2 setup on their tank. Citric Acid and water in bottle A... Baking Soda and water in bottle B. Squeeze some from A into B to start the reaction and prime the system, and after that it's going to force more Citric Acid in to re-start the reaction any time the pressure drops by enough. I've only had it set up since Friday, but I haven't had to touch it since. I thought it would require way more fiddling to keep it running. The amount of CO2 it can put out doesn't look like much in the bubble counter, but it's actually more than my diffuser is capable of handling, so I've had to turn it down quite a bit. Still keeping the CO2 indicator in my tank a nice shade of "light green"

Recurring cost
I bought a bag of Citric Acid and a bag of Baking Soda from Amazon. Both were $15 for 5lbs (2.3kg). Each fill up uses 200g of material, so you should be able to get 11 fills out of each bag, $30/11 comes out to about $2.72 per fill-up, and that's about every 2 weeks or so.