CO2 Questions

**lighthouse** · 23rd Apr 2009, 09:46

Hi deon,

Thanks for the clarification. :-)

Strangely, my Max Mix CO2 reactor seems to have only 1 top impeller (not 2) that spins just underneath the CO2 inlet, and another fin-like piece at the bottom of the reactor. Perhaps, the difference could be that mine is the Medium sized variant, and not the Large type??

On closer inspection, this lower piece seems movable along the shaft and "turn"-able (verified upon opening up the reactor). Hence, I originally thought it should spin as well. But as you've clarified, I guess it should be for directing the water-flow, since it doesn't seem to be anchored vertically to the shaft...

Thanks once more for the inputs. :-)

**monster_88** · 29th Apr 2009, 09:07

I am totally new to this and have just bought a CO2 system hoping to try out a planted tank. I have a small nano tank; one of those that comes with everything including filter and lights. It's about 27 - 30cm wide.

Just wondering, why do we need to use an electronic timer controller to switch on and off the CO2 system? What will be the difference if the system is left to bubble the whole day, but at a lesser rate. For example, if recommended to use 1bps for eight hours, then for 24 hrs, I use 1/3 the rate but without any on off cycles. Can it work? Wouldn't it be more stable in terms of CO2 concentration in the tank over the period of time?

Thanks

**Philosophos** · 3rd May 2009, 05:11

Plants only uptake CO2 during photosynthetic periods. When there isn't light, they switch in to cellular respiration; they absorb O2 and give off CO2. You can pay off a solenoid in 3-4 years of running a 20g on compressed CO2 if I remember right. It takes less time for larger tanks, of course. Here's an article on the rest of it:
http://www.thekrib.com/Plants/CO2/night.html

You can do either one, personally I like letting the aquarium gas off at night; a lot of aquarium plants are bog plants. They are used to a pH swing at night, and what should be a higher nitrate level. I can't see simulating it being harmful, so it's not a bad addition to saving money.

-Philosophos

**monster_88** · 8th May 2009, 02:09

Thanks!! Really appreciate the info. Didn't realise that the effect of CO2 is so complicated.
Another thing, I realised that the 10hrs ON time for lights and/or CO2 injection is supposed to be in the 'day' time. I have been setting my lights 10hrs sequence in the night time; ie. from 7pm - 5am. Is this a problem for the fishes and plants? I do this because during 'daytime' I'll be at work so setting it this way allows me to appreciate them when I'm home at night. Is it still OK?

**Philosophos** · 8th May 2009, 03:47

So long as you've got the room or aquarium its in blacked out during the day, it should be fine. Otherwise, I've got no clue how little light will mess up cycles. My little 1 watt LED moonlight over my 20g hasn't hurt anything so far.

-Philosophos

**monster_88** · 10th May 2009, 16:52

Actually, one of the tank is in the living room. So it's not really that dark nor is it bring enough without the artificial lighting.

Generally, is it 'normal' practice that lights are kept on in the daylight hours? Then, if we want to watch the fishes in the evening, the lights will be ON more than 10hrs a day right?

**Philosophos** · 11th May 2009, 02:31

My lights go on at 11am and shut off at 10pm with a 2 hour break from 3-5pm. I tend to shut the blinds at night, so light doesn't get in during sunrise.

-Philosophos

**monster_88** · 11th May 2009, 17:23

OK, so can I assume that the CO2 switching times are also aligned with the lighting? Including the 2 hours break? Thanks

**Philosophos** · 11th May 2009, 22:59

Ya, change the CO2 with the lighting. I stagger my CO2 from the 2 hour break; CO2 shuts off before the light, and turns back on before. It takes time to gas-off and re-establish. Whether this is 100% the right way or not is something I haven't looked in to a whole pile; most of what I've heard and read on the subject is pure conjecture.

-Philosophos

**MrSpock** · 25th May 2009, 17:15

I also have some questions about CO2 that so far have not been discussed in this thread. Hope some kind sifu can cast some light.

1. Exactly what components make up a CO2 system? (I hear things like solenoids, diffuser, reactor, auto, manual....

... at a loss now!)

2. Is there a good link to read up about CO2 systems and how to use them?

3. Generally how much do they cost?

4. Is it reliable to get a 2nd hand set? (I see a few ads in the marketplace forum).

5. Can a CO2 system be substituted by products like Seachem Excel Flourish?

Thanks kindly for your answers.

**Jimmy** · 25th May 2009, 17:25

http://www.greenleafaquariums.com/pl...m-diagram1.jpg

http://aqua-ca.com/images/co2%20system.jpg

**Philosophos** · 26th May 2009, 00:12