View Full Version : CO2 into sump
ArkyLady
07-24-2003, 5:18 PM
We're building a shelf to house two 30 gallon and two 10 gallon planted tanks on it. I'm planning to connect all of these to a central sump system to simplify things.
My question is, can we inject CO2 directly into the sump, then pump the water up into the tanks without losing most/all of the CO2? It seems to me as long as the returns in each tank were under the water so it didn't create surface agitation that this would work. Am I wrong?
Rocketman
07-25-2003, 2:45 PM
I remember askin something like this awhile ago...
I remember something else about another, different post asking if you could use a canister on two tanks, (15 and 60) and the answer was no, because you would end up with 60 Gallons of water in the 15G tank. Are you sure your central sump idea will work? You may want to get the physics worked out first.
perrush
07-25-2003, 4:42 PM
@ Arky Lady :
ofcours a sump will loose some CO2, and if it is constructed badly, it can loose most CO2.
As for the contruction part :
- Make sure your water is never 'falling', but 'running'. Instead of making the drainage straight down, make it in an angle of 45° or even less, if you have too just make some turns.
- the outcome of the pipe is best underwater, again no falling.
As for the injection :
- inject your CO2 after the bacterial beds. The micro organism produce CO2 itself, and the lesser CO2 is in the water the better they can 'exhaust' their CO2.
Still you will loose CO2 but maybe it's workable.
( I'm planning to do the same, so lets hope it works )
125gJoe
07-26-2003, 7:39 AM
My opinion is to use a "Power Reactor". You can have it inside the aquarium or outside, hidden behind it. The reactor is simple and can produce 100% diffusion. I'll try post a pic for you...
When you mention 'sump' this means you are using a Wet/Dry type filter -- correct?
ArkyLady
07-26-2003, 12:20 PM
Rocketman: Each tank will have an overflow to allow the water to return back to the sump and I can control the amount of water flowing into each tank with valves. No way for the tanks to flood unless the water is coming into them faster than the overflow can return it back to the sump. I have a betta barracks system on a central sump/filter, the "tanks" on that system range from 1/2 gallon to 25 gallon and it works fine :)
perrush: Great info, thanks. I'm going to try it and see how it goes. Worst case scenario I'll have to resetup my CO2 so that it's injecting to each tank seperately which won't be a huge problem. I'm just determined to build a setup where there is zero equipment in the tanks.
80gJoe: Yes, it will be a DIY wet/dry.
I've also thought about just going completely filterless and just injecting CO2 into each tank with a powerhead to keep some water circulation going, but that still makes me have to put a heater in each tank and do water changes on each seperately. On my betta barracks system, I have an auto top off so when I start removing water it automatically adds fresh water back into the system from a large rubbermaid trashcan filled with heated, conditioned water. This has really spoiled me! So I wanted to use a similar setup in the house with all my tanks.
125gJoe
07-26-2003, 12:54 PM
Originally posted by ArkyLady
... ... Worst case scenario I'll have to resetup my CO2 so that it's injecting to each tank seperately which won't be a huge problem. 80gJoe: Yes, it will be a DIY wet/dry.... .........Doing the CO2 that way will give the best results. CO2 is easily "off gassed" so you don't want CO2 enriched water "flying through the air" as a Wet/Dry tends to do.... ;)
...waiting to get slammed by Wet/Dry owners... lol
Actually, commercial W/Ds and well-constructed DIY W/Ds do not blow off much CO2 at all. The overflows blow off more than the W/D, and they can be covered to reduce if not eliminate that.
And I too use sumps and W/Ds on multitank systems without significant problems. Once you have the concepts of overflows and constant-level siphons it is not that big a deal. Redundancy is good, but with sufficient flow margin in an overflow may not be required.
Anyone who has worked with a central betta system should have no problems at all.
Nasty curiosity - ignore me if you wish, but have those of you saying nay ever operated a W/D and/or a central circulation system?
125gJoe
07-27-2003, 1:57 PM
I enjoy the fact that 'canister filters' are a 'closed system' with no chance of "gassing off" CO2. The 'return' or 'outlet' tube from the canister can be placed low, so there's no surface agitation in the tank to diminish CO2. ..it's so nice...
:)
Wet/drys are good filters too, and have their place....
Excepting of course the Eheim Wet/Dry - which breathes. It may be the only canister not in total adding CO2 to the water, but I have not done the balance to confirm how well it breathes.
This may be useful to you (http://aquaticconcepts.thekrib.com/Co2/#loss)
125gJoe
07-28-2003, 8:01 AM
Originally posted by Jhong
This may be useful to you (http://aquaticconcepts.thekrib.com/Co2/#loss) Guess I missed something as the first chart shows no CO2 past 6 hours..
Now the Eheim Wet/Dry is a "closed" type filter where it seems there would be minimal CO2 loss.
The Eheim W/D is not closed - it breathes by pulling ambient air in during the water return to tank portion of the cycle, purging that during the canister water refill portion of the cycle. That is why it is a W/D. It is the only open canister I know about.
Originally posted by 80gJoe
Guess I missed something as the first chart shows no CO2 past 6 hours..
.
I think that is a misinterpretation of the results. Without the W/D, the CO2 fell to below 10.5 in 8 hours. With the W/D it took 7 hours. The main cause for loss was found to be turbulence.
125gJoe
07-29-2003, 3:34 AM
Originally posted by RTR
The Eheim W/D is not closed - ... Guess I read it wrong in the recent Doctors Foster Smith catalog pg. 15...
"Completely closed system - Cannot Overflow!"
"Exchange of oxygen and CO2 is accomplished by means of displacement through the specially designed breathing tube."
It goes on and says, "The water output pulsates as the filter fills and empties, achieving a wavelike action."
How much wavelike action? Maybe it's best to leave 'wavelike action' for reef tanks - where those critters enjoy waves.... ;)
It would be interesting to see the effect...
The vent line is small and attaches to the tank above the waterline, so it will not overflow in power off or such condition. But it is open. Knock the vent line loose and leave it on the floor and it will drain the tank - but so would having the same thing happen to the water return line from this or any other canister, and that would be much faster. The Eheim W/D is an open system. Ask Eheim. Perhaps the ad writer at the supply house does not know what a W/D is.
W/Ds use atmospheric exchange for O2 and CO2, without that they are not W/Ds. But Eheim engineering would never turn out any filter which could easily overflow with correct assembly and configuration.
"Wave-like action" is a poor joke. Think of it as a pulsed return, of the relatively small exchange volume within the canister. It is not a dump bucket I promise you.
Dabbler II
07-29-2003, 1:25 PM
It took me about 3 months to get my system working properly. I have a reef ready tank with over flow and a wet dry sump under my tank. I tryed dumping my co2 in the return pump and I bought a power reactor still nothing... no co2. I hade to raise my over flow in my tank till it was only 2" below the water level in my tank before I could get the co2 to stay in the water. I am still pumping in alot of co2 into tank but I am now steady at 6.9 for ph from 7.8. It will work but you need pressured co2. My reactor is in my sump
125gJoe
07-29-2003, 2:45 PM
Originally posted by Dabbler II
...... I tryed dumping my co2 in the return pump and I bought a power reactor still nothing... no co2. I...... I am still pumping in alot of co2 into tank but I am now steady at 6.9 for ph from 7.8. It will work but you need pressured co2. My reactor is in my sump That's my point exactly. There's too much agitation causing off gassing of the CO2. Simple.. Pumping in more to counteract this is fine. It's how the Wet/Dry operates that causes the gassing off of CO2.
For those who haven't seen a Wet/Dry working up close - there's a rather large 'waterfall' going on in one of these devices - water spilling on to 'bioballs'....
Dabbler II
07-29-2003, 3:12 PM
there's a rather large 'waterfall' going on in one of these devices - water spilling on to 'bioballs'
The bio-balls wasn't the problem it was the "water fall" in the over flow part of the tank thats where the gassing off came about.