What Co2 Cylinder ?

[michaelwgroves]

I have a 900 Litre planted tank. I'm going to setup a pressurised Cylinder CO2 system.
I have heard people using CO2 cylinders from Fire Extinguishers, Pubs, BOC and Welders, but I'm not sure what’s best. There seems to be a plentiful supply of fire extinguishers on eBay for under £30, but I had a quote to refill from a Fire Extinguisher company of £25 for a 2KG.
BOC charge £44 per year rental for a 6KG and only £8 to refill.

Before I purchase anything, can anyone tell me how long a 2KG cylinder is likely to last in a 900 litre aquarium?
Secondly, where is the best place to purchase a cylinder, and also where is the cheapest place to get them refilled?
I work to Tunbridge Wells, Kent if you know somewhere local for cheap refilling?

 

[Musho3210]

You probably know this but make sure it specifically says CO2 cylinder engraved into it. Otherwise you might not be able to get them refilled.

 

[zig]

A 2kg cylinder will not last long on a 900l tank, a month maybe? but I guess it depends how much CO2 you want to inject, running a 900l tank as a highlight venture would be hard work. The major problem for tanks this size is distributing the CO2 effectively in the water column, you will probably need multiple points of injection/diffusion for it to work properly.

You would need to do a good bit of research before you start, at a guess on cylinder size, at a minimum you would need to look at 5kg size cylinders, these would be the equivalent of US 10lb tanks, even better would be 10kg CO2 cylinders, but you may need a couple of them to make it work properly for you bearing in mind different points of CO2 injection.

Good luck with your tank.

 

[rsands]

a couple of the big powered diffusers is whats needed really...they will fairly blast it around if you get one of the big ones.

is that the tank in your sig? looks well all built in

 

[michaelwgroves]

Blimey, one month................
Okay so I will need a big one, I'll look around to see what I can buy.
Can anyone recommend the cheapest refill option, brewery, Fire Extinguishers, Welders etc.

Could I not have a single cylinder with a Tee-piece running to each of the diffusers, that way I would save money as I would only need one Regulator, Needle Valve, Solenoid, bubble counter & non-return valve?

"Big Powered Diffusers", can you recommend a manufacturer so I can take a look ?

What do you mean "running a 900l tank as a highlight venture" ?

Yep, that's me tank

 

[2pods]

My 2kg FE has been running for 3-4 months so far on a 400L tank through an external reactor.

 

[michaelwgroves]

My 2kg FE has been running for 3-4 months so far on a 400L tank through an external reactor.

Where and how much does it cost to get your 2KG cylinder refilled?

What External reactor are you running?

 

[BigIan]

For a tank that size if you have some where to hide it i`d get a BIg 15kg (I think) cylinder from calor gas, its 20 quid to buy the cylinder (no rent) and then roughly 17 quid to re fill it.
but the large cyinder is aprox 4 ft tall

And as for the Tee piece idea to split the co2 it didn`t work for me, i couldn`t get the co2 to spread evenly between the 2 diffusors in my tank and i can only atribute that to my black bear algae infestation

 

[2pods]

My 2kg FE has been running for 3-4 months so far on a 400L tank through an external reactor.

Where and how much does it cost to get your 2KG cylinder refilled?

What External reactor are you running?

A local guy does it for £13 picks up and delivers

this is from German ebay power sellers Aquamas .

 

[zig]

Well my guess of one month was only a guess, hence the question mark after it, I have a 2kg fire extinguisher on a 54 litre tank and it lasts just over a year, CO2 is run via a solenoid at 1bps, so go figure.

What levels of CO2 are you trying to achieve, for low levels, a 2kg may last you quite a while but if you are aiming for 30ppm you are going to need something bigger on a 900l tank IMO.

The biggest problem you will face will be distributing the CO2 evenly in the tank, I'd suggest you look over on the planted tank and look through some of the threads over there in the relevant section to get some ideas, an external reactor/reactors is probably the way to go.

"big powered diffusers" I presume the poster is talking about powerheads, you can hook a CO2 line into a powerhead and the impellor will chop up the bubbles and spit them out the other side into the tank, personally I would still reckon external reactor/reactors is the way to go.

All the above is just my humble opinion you understand, I do not have a 900l tank, I would say the planted tank is a good place to look for ideas, lots of guys over there would have run large tanks and faced the same problems.

 

[JamesC]

As Zig mentioned it all depends on what levels you wish to achieve. When I used 2kg fire extinguishers they lasted me about 2 months on my 210 litre tank. I now use a 6.35kg pub bottle and that lasts about 6 months and costs £15 + VAT to refill.

James

 

[michaelwgroves]

Calor Gas sounds the way to go, I can accommodate up to 4ft under the stairs. I checked out the Calor Gas web site, but they don't mention CO2. I've sent them an email for some more information.

James, where do you get yours refilled ?

I had an email from George Farmer, he recommended 20-30ppm CO2 as a good starting point. He did also advise 2 cylinders, so I guess I'm just gonna have to bite the bullet and double up on everything.

Zig, I'm confused about your advise to look at the planted tank, this is the planted tank forum, is there another ?

2Pods, That looks a beast, I can see pipes running off everywhere, What are the Blue and green things, how does it work?

BigIan, Black Bear Algae, that sounds nasty, how did you get over the T-Piece problem in the end?

 

[2pods]

2Pods, That looks a beast, I can see pipes running off everywhere, What are the Blue and green things, how does it work?

It's just the external filter (grey) which output goes into the top of the reactor (thing with green sponge in ) as does the Co2 from the bottle via a non-return valve.
This is dispersed in the reactor and comes out the bottom of it to the UV sterilizer (Blue) and then back to the tank. The solenoid is on a timer with the lights. This switches off the Co2 at night when it's not needed and switches it on again at lights on. Excuse my lack of PSP expertise, but the pic my help.

 

[JamesC]

James, where do you get yours refilled ?

I get mine from Maison Maurice in Bexleyheath which luckily is about 1 mile from my house. Take the empty one in and pick up a filled one. Back home in minutes. Probably a bit far for you to come I'd thought. Take a look in yellow pages for soft drink and beer suppliers. I contacted Calor gas a while ago and was told they don't do CO2. Even their website has no mention of CO2.

You can run several diffusers off one bottle but it means having to buy a splitter and a needle valve plus bubble counter for each diffuser you run. People do it and is fairly easy to do.

James

 

[michaelwgroves]

I've done a bit of ringing around for prices, I'm gonna try Maison Maurice tomorrow to see if they will deliver to Tunbridge Wells. But my figures so far are;



This is based on no delivery costs although BOC charge you can exhange cylinders locally. Yearly costs are accumulated as some are cheaper the longer you have them.
Air Liquide appear to win in both the short and long term, although purchasing a Fire Extinguisher off eBay or London Gases (AKA London Beer) do catch up in the later years. Although it's worth mentioning that London Gases will also do larger cylinders at th same price if you can accomadate them. This makes them by far the cheapest. Although I'm not sure if CO2 has a sell by date?

2Pods
So if I was to use an external reactor like yours, do you think my filters twin output would blast the CO2 around enough ?
What make is your reactor, and can you la them on thier side?
I like the idea of your reactor as it keeps equipment out of the tank. Also what alternativs are there to your reactor?