CO2 control? - The Planted Tank Forum
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post #1 of 8 (permalink) Old 07-15-2005, 10:07 AM Thread Starter
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CO2 control?

I'm after some general opinions and experiences with CO2 control/non-control methods.

Presently I have 2 x Nutrafin units in my 34G giving me a constant 25 to 30ppm - I change the mixtures every 7 days or so (staggered). Obviously the units are running 24/7.

I'm upgrading to a pressurized system soon and am wondering is it worth either 1) using a night shut-off solenoid 2) with pH controller or 3) running 24/7.

Obviously the cheapest option is to run 24/7. How many of you guys do this?

Those that use a solenoid without pH controller - do you have it coupled to the lights or on a seperate timer (I was thinking perhaps to come on before the lights to get CO2 levels up prior to lighting).

Those that use pH controllers - how often do they need calibrating and how often do you measure your KH?

Thanks in advance.
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post #2 of 8 (permalink) Old 07-15-2005, 10:51 AM
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what most people do is to have the solenoid valve plugged on the same timer as the lights.Then they play with the amount of co2 injected so they keep their pH in a "stable" value according to their KH through out the day.I personally believe that is almost imposible to keep your pH constant manualy,too many parameters change through the day that change the pH if the amount of co2 is the same the whole day.In the case of pH that you have to deal with logarithms a few changes of +/- 0.1 to 0.2 can make a lot of fluctuation on your co2 level.Obviously a pH controller is the best choice and I believe that makes a difference between algae and no algae.I believe that Tom Barr knows what he is doing when he is talking about more co2.

Regarding KH you do not have to measure it except between water changes.The compound refered to as KH is always present at the amounts you initially put but make sure that you top of water lost by evaporation with distilled or R/O water.

My pH controller needs calibrating every 3 months,other brands may be different...
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post #3 of 8 (permalink) Old 07-15-2005, 11:19 AM
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As I recently (4 months ago) switched to pressurized and DIY'd past the regulator using spare parts, I'm on the 24/7 method. CO2 is bubbled into one of my canister filters. Generally up to a 0.2pH swing throughout the 24-hour period. No ill effects on the fish as far as I can see. Yes, I'll go through the CO2 faster than others but for now I'm fine with that. It does take a bit of finessing to get the bubble rate where you want it though. With a controller the bubble rate is fairly irrelevant.



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2g Mac-quarium. Clown gravel, fluorescent plastic plants, and 2 guppies.
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post #4 of 8 (permalink) Old 07-15-2005, 12:16 PM
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Manual systems (two of them) both on 24/7. I find I get less pH swing with the CO2 always on than I do if I turn it off at night.
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post #5 of 8 (permalink) Old 07-15-2005, 07:51 PM Thread Starter
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Thanks for the input guys. Any more people willing to share there methods/experiences/opinions? I'm assuming 90% of the people reading this use/have used pressurized CO2.
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post #6 of 8 (permalink) Old 07-15-2005, 08:04 PM
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Before I made the switch to pH controller, I just keep CO2 turned on 24 hours a day. Fiddling around with injection rate vs surface movement a bit should get you a fairly stable CO2 level day and night, within +- 0.2 should be easy.

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post #7 of 8 (permalink) Old 07-15-2005, 08:10 PM
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Mine is on 24/7 at about 3bps and it gives me around 30ppm. Even at this rate my 5lb tank should last for at least 4-5 months and at $10.00 a refill I can afford that.

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post #8 of 8 (permalink) Old 07-15-2005, 11:55 PM
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I am setting up new 37 gal cube tank (by Oceanic). I want/need healthy plants and lowered, but not necessarily constant pH (4-6) for the fish.

I was thinking of using DIY/Nutrafin set up because I've used the Nutrafin chamber (with a DIY yeast recipe) and ladder split between 2-2.5 gal, and on a 5 gal, a 20 gal, and 29 gal tank with no known issues. And, they've lasted me longer than 7 days (20-25 days). The Nutrafin is rated at "up to 20 gal." per yeast chamber.

- Hmmmm... Do 90% here use pressurized for this size tank? For what other reasons should I be looking at switching to pressurized? ...or staying with DIY?

- I also see another here talking of injecting CO2 into the water at/via their canister filter. How do you control the flow? What kind of equipment is there for pH or bps control for canister injection? How does canister peat filtering affect injection? What kind of DIY vs pressurized set up does one need to work with such injection?

- How does the mode of delivery (canister injection vs...) affect CO2 control choices and benefits/trade-offs?

I'm learning a lot, TIA...
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