I got a CO2 system...may I have more advice?

[klinikal]

Hi all,
A while back I wrote asking for some help with my planted Discus tank. I received lots of ideas. The most common suggestion was to get a CO2 system. Well, I did.

The tank is 120 gallons 4'x2'x2'. Echo Complete plant substrate. A 5lb bottle of CO2, pH Controller, solenoid valve, CO2 reactor and bubble counter.

This is where I need some advice:

1) How long does a 5lb bottle typically last? I will try to keep my pH at about 6.5-7. The water hardness is soft but I am still working out just what the values are as I just started adding more "R.O. reconstitute" to my R.O water.

2) How many bubbles per minute work for you? What do you suggest?

3) I understand that the more calcium carbonate in your water with a lower pH means more CO2 in the water...is this correct?

Thanks in advance for your replies.

Chris

[anti-generic]

you can check out this co2 chart
http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

to find out the relationship between co2 density, ph and Kh.

as for how long the bottle would last.
it really depends on how much you are dosing into the tank.

some ppl dose high amounts to match high lighting and ferts

some ppl dose just enough to have decent plant growth while keeping algea at bay

Cheers,
Eric

[Bad Inferno]

If you have a ph controller who cares about bubble count..I just have a high quality ceramic airstone that the CO2 bubbles through when the controller opens the solenoid. Still it only has a small amount of tiny bubbles when the solenoid is on. When turned on I can see my pH start to move within 1 minute. I have an inline probe so it will depend where you place your ph probe in the tank.

Placement of your probe together with the amount of CO2 injected (your bubble count) should see the meter change within a couple of minutes I would of thought.

I achieve a ph within +-0.02 ph from setpoint and run mine at 6.4 with a kh of 2 & from memory this should give me a co2 of ~20 ppm

Try this chart, I like the green band of safe co2 levels.
http://users.bigpond.com/rohan.t/co2_chart.htm

My CO2 bottle is a 7kg fire extingusher (spelling doh! ) and its run for 18 months thus far. I have a 200l tank

[TomNS]

My CO2 bottle is a 7kg fire extingusher (spelling doh! ) and its run for 18 months thus far. I have a 200l tank

How did you get your fire extinguisher bottle filled with CO2, I am guessing you changed the top on it but who refilled it ? I wouldn't think that you would be able to have this done by BOC or AirLiquide or the like

Cheers
Tom

[klinikal]

Eric and Bad Inferno,
Thanks for your replies and thank you for the charts. My solenoid valve and pH controller worked today. I came home and the CO2 was obviously running to the point where my controller turned it off. So whew! That works!

I am currently having a difficult time fine tuning my flow rate to stay consistent. I will set it and an hour later it has stopped.
I have checked the forums and I think I need an inline needle valve after my 2 dial regulator so the regulator can keep the pressure up and the valve to constrict the gas flow.....is this right?

My algea problem persists though. Now instead of the algea receeding it is producing oxygen bubbles from so much photosythesis. Arrrgh!

I think I am going to have to take the system down and start fresh.

Anyways, thanks

Chris

[Bad Inferno]

I DO need a needle valve after the reg