My First Foray Into Diy Co2

[volenti]

I have a 4' 320L tank I'm "practicing" this on in preparation for my 6' 380L tank (being set up) which will be my "serious" planted tank.

Instead of soda bottles I'm using a 19L stainless steel home brew...thingy I borrowed off a friend who is into that, I figured the larger volume may be productive enough to do away with the expense of pressurised CO2.

I used an empty peanut butter container (Kraft of course) as the gas seperator and a gravel vac full of bioballs for the powered reactor that runs off a T on the return line from the sump through a ball valve. I had intended to have the reactor inline but water pressure issues prevented this untill improve the design (my sump return pump is an Iwaki MD-20RZ which does not muck about)

Now this tank is set up with a wet/dry sump so I know I've got too much gas exchange (though I've tried to minimize it as much as possible) but I still have enough CO2 dissolved to lower the ph from ~7.5 to ~7 (KH=3 buffered with coral peices from the tap water KH of 1) so it looks like it's working, I think I have some very minor pearling on some of the plants, lights are a grow-lux tube, a 5000k and a 6500 tube (3 in total)

The CO2 generator
http://users.bigpond.net.au/volenti/DIYCO2.jpg

CO2 reactor
http://users.bigpond.net.au/volenti/DIYCO22.jpg

Gas seperator
http://users.bigpond.net.au/volenti/DIYCO23.jpg

T and ball valve
http://users.bigpond.net.au/volenti/DIYCO24.jpg

Tank shot
http://users.bigpond.net.au/volenti/DIYCO25.jpg

Any comments/suggestions? especially recipes for the CO2 generator, this run I used ~15L water, 2kg raw sugar, 1x 7g bakers yeast satchel and a half tea spoon baking soda.

[wombat1100]

thats a gr8 lookin tank you have there , I love the timber in the centre , very natural looking.
Dazz

[joz]

Looks good.
Though does it turn off at night when its of no use to plants??

Your right about wet and dry,they diffuse any CO2 out of the water so quickly,they seem to work against each other.

[volenti]

Looks good.
Though does it turn off at night when its of no use to plants??

Your right about wet and dry,they diffuse any CO2 out of the water so quickly,they seem to work against each other.[/b]

At night with this setup I don't bother turning it off (well you can't really turn the yeast off, but it slows down a bit in the cool of the night)
the dissolved CO2 level doesn't get high enough to cause problems for the fish even without the plants absorbing it. (go go wet/dry)

I have a few options for when I apply this to the intended tank though , which being well sealed and using canisters for filters, should
build up a lot higher concentration of CO2 (30ppm is the common goal, 10x the normal concentration)

I can pop off the fitting on the brew cylinder which will seal it and build up CO2 pressure(it's rated for 130psi and has a relief valve) and get a big burp of co2 in the morning when I plug it back in, some will fill the reactor to slowly dissolve into the water and any excess will vent off into the air. This may be my desired option since I can alter the brew mix for "slow burn", store the morning burp in a large reactor and get maximum run time between refills.

Or I can simply put a T in the CO2 line with a valve and let the CO2 vent off at night.

I'm already using multiple timers to control the lighting, another to operate a solenoid valve or similar for the CO2 is no issue.

I'll make a thread documenting the setup of the new tank.

[wombat1100]

I look forward to hearing how you set up your final model, I am still toying with the idea of putting a co2 in my planted tank but I am concerned as i have already got an algae problem in that tank because its close to a window.
Is this the case? will it promote increased algae growth?
Dazz

[volenti]

I look forward to hearing how you set up your final model, I am still toying with the idea of putting a co2 in my planted tank but I am concerned as i have already got an algae problem in that tank because its close to a window.
Is this the case? will it promote increased algae growth?
Dazz[/b]

That tank will have algae problems from it's location CO2 or not, though with moderate injection+nutrients and better light control you could tip the balance towards the plants, it may take a series of blackout periods (3 days of 0 to very low light) to keep the algae under control until the plants become established enough. Plants like stability, it can take a week or 2 for plants to adjust to new conditions and that lag gives algae time to take hold (this lag is also what lets plants survive the blackout)

I have the 6' tank set up now and everyone is settling in, I've re-designed the CO2 reactor and am pretty happy with it's performance. It's now running of a dedicated pump (based off a cheap $10 internal power filter from big W) The CO2 is piped into the intake of the pump to help chop up the bubbles before the stream enters the reactor, a deflector then directs the stream so it spins the water as it flows down the tube, this turbulence breaks up the bubbles further, the flow then enters the bottom of the uplift tube (still spinning inside the tube) and is directed out the top along with very fine bubbles (the type that drift around instead of floating to the top)

http://users.bigpond.net.au/volenti/vortexco2.jpg

Dissassembled,This shows the internal pipe (UGF uplift tube) it helps direct the water flow around in a big dohnought shaped spiral, this is critical since if it isn't there the bubbles collapse into thin "tube" of gas at the center that doesn't diffuse very well.

Some shots of the deflector;

http://users.bigpond.net.au/volenti/vortexco23.jpg


http://users.bigpond.net.au/volenti/vortexco24.jpg

in tank shots, you can see some bubbles swirling around towards the top of the tube;

http://users.bigpond.net.au/volenti/vortexco26.jpg

http://users.bigpond.net.au/volenti/vortexco27.jpg

I played around with some smaller versions, this is the best performer, made from those little plastic nicnack containers and some bioballs to prevent the aformentioned centeral vortex from forming and a crude eductor on the output to give a bit of boost to the flowrate,wasn't enough for my 6' but would do well in a smaller tank (55gal and under)

http://users.bigpond.net.au/volenti/vortexco28.jpg

For smaller tanks still (~100L and under) you can simply take the sponge that comes with the pump and mount it on the output, the pump blasts the bubbles into the sponge which does quite a reasonable job of diffusing them, a very quick,cheap and easy way to do diy co2 in a smaller tank.