# HELP!!! sump and co2 ?



## bienlim (Feb 10, 2006)

hi guys, just wondering if u can help me, i will be setting up a tank (125 gal) for a friend of mine and he wants to use a sump and i heard u lose co2 this way so just wondering how much co2 is losswhen u use a sump........thanks


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## Zapins (Jul 28, 2004)

Hehe, most of the CO2 is lost using a sump. Its sort of like having a bottle of soda and shaking it - all the CO2 is degassed. Your friend won't need a sump for a freshwater. 

By any chance did your friend come from a saltwater background??


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## bienlim (Feb 10, 2006)

yes he did..lol


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## Questin (Sep 30, 2007)

He must have a sump left over from that part of the hobby. If he has to use a sump, make sure to get him into all the CO2 less types of plants, and then you can always just use Flourish Excel if you get into the more demanding plants.


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## bienlim (Feb 10, 2006)

good thinking but in a 125 gal that can get expensive


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## Zapins (Jul 28, 2004)

No point to adding a sump to the tank. In salt water sumps are used to grow algae to remove nutrients, in freshwater planted tanks you need to ADD nutrients so a sump is pointless to say the least. Its not as if he needs to expand the volume of water for a more stable system, its a 125g tank so its big enough lol.


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## Gilles (Oct 12, 2007)

Zapins said:


> Hehe, most of the CO2 is lost using a sump.


That is not true, the sump is not the "reason" for the co2 loss, in fact, i have a planted tank with a sump and a few winners of the National Aquascaping Contest here in the Netherlands also have a sump and won. So to answer his question:

- Does a sump cause co2 loss: No, if the overflow is regulated in such a way that the water flows to the sump (e.g. not a waterfall) no degassing is caused there. In addition, you have to make sure the sump is covered by glass plates. Yes a sump increases the surface of the water, so yes more degassing takes place. But this can be seen as the same with a larger aquarium. E.g. more surface cover == more contact with air == more gass loss.
- Does a sump require you to add more nutritients? Yes and no, Yes if you have materials that take up nitrates and so on, but no if you only filter using thesame filter materials that you would use in a "normal filter".

But, take care! A good potfilter has about 35 liter filter materials, my sump has 125 liters, so it filters much MORE!


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## Questin (Sep 30, 2007)

Is a sump filter for a freshwater tank on the same level as the tank itself then? How do you get around not having a waterfall?

And would you have links to the winning tanks with sumps, I would love to see them.


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## Zapins (Jul 28, 2004)

Gilles, I see your point. However, an ordinary sump will cause CO2 loss if it is set up as I have seen every single saltwater sump. All the ones I have seen use an overflow to direct the water into the sump. If you shake up the water and the tube its in is not pressurized then the CO2 will degas. I believe bienlim was asking about this kind, not the kind you mention.

Is it possible to modify a sump system so that there is minimal CO2 loss? Sure, (like you said) but this takes some doing, and isn't the typical type of sump. 

To rephrase: The sump container doesn't cause CO2 loss by itself, its the water that splashes and into it from above from the overflow that causes it.

I maintain, a sump is not a necessary for planted tanks, it only adds unnecessary complexity to the system IMO. What are the benefits? What are the costs?


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## Gilles (Oct 12, 2007)

Zapins said:


> To rephrase: The sump container doesn't cause CO2 loss by itself, its the water that splashes and into it from above from the overflow that causes it.
> 
> I maintain, a sump is not a necessary for planted tanks, it only adds unnecessary complexity to the system IMO. What are the benefits? What are the costs?


Amen to that. I will try and get my new 80 gallon tank i am building now up on this forum, then you'll see what i mean. Metallic frame is bought, and will be done next week.

Regards
Gilles


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## Chuppy (Aug 5, 2007)

Just wondering.. if this is so.. i seen some c02 domes before... do they help?

Drew


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## mrkookm (Oct 25, 2006)

bienlim said:


> hi guys, just wondering if u can help me, i will be setting up a tank (125 gal) for a friend of mine and he wants to use a sump and i heard u lose co2 this way so just wondering how much co2 is losswhen u use a sump........thanks


While it is true a canister is more efficient at Co2 usage and a tank from what I hear can last for years, maintaining Co2 @ correct levels is possible without much Bps in a sump environment if *proper diffusion method is used*, I know this because I am doing it. I am maintaining a limegreen DC with only 5Bps and my setup consists of a 90gal, a CPR CS150 overflow in which I have placed a Durso standpipe, not to retain Co2 but too reduce noise and a 30gal sump. The water from my tank is not directed underwater, it is filtered through a micron sock which gets dispersed over another layer of coarse filter media, then finally over a Biowheel and I have no special covers to retain Co2.

IMO I think the sump / Co2 loss explained above is exaggerated and you do not lose much Co2 as stated. If I can maintain a limegreeen DC with 5Bps on a 90gal how much less is needed in a canister setup?

While I will suggest a canister filter for ease of use over a sump don't be discouraged in using your sump on your tank as needed Co2 levels can be maintained. Take a look at this *Reactor*, this is what I am using currently with excellent results and prior to this I was misting with a Rhinox 5000.

Now the important thing with a sump setup is the final flowrate that is used 'tank turnover rate' this should be around 600gph with *less being better*, anything over and you are asking for trouble, remember this is not 'saltwater' :-D.

Here are some plants in my 90gal sump setup....see my sig also........



















When I was misting with Rhinox as you can see *healthy unstunted growth*









Using a sump on a planted tank is possible as I am using one now and I have no fancy setup to prevent loss of Co2.


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## aquaman3000 (Dec 1, 2005)

As mrkookm stated, there is no problem using a sump in a planted tank. CO2 loss in sumps is exaggerated imho. They do add more complexity and expense as mentioned, but to me are worth it to hide equipment, maintain the water line, grant easy access, and provide more water volume. My setup is show below, and I have no problems maintaining CO2 levels, and can easily cause the fish to gasp at the surface if I crank it up. Your mileage may vary.


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## bienlim (Feb 10, 2006)

thanks guys, we set up the tank today( so tired ) did nit have a chance to run the coe coz we dont have any tools to tighten the reg. so will have to do it tomm.then will measure the water after a day or 2 to how much co2 we need to inject....thanks


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## Zapins (Jul 28, 2004)

Hmmm, nice pics guys, I especially like the PVC pipe fixtures. If there is something I'd recommend to everyone its making your cabinet neat and tidy by hooking everything up to custom made PVC pipe setup. Definitely minimizes in-tank clutter. 

Interesting Q you raised here 

"IMO I think the sump / Co2 loss explained above is exaggerated and you do not lose much Co2 as stated. If I can maintain a limegreeen DC with 5Bps on a 90gal how much less is needed in a canister setup?" 

If the water splashes or goes through a wet-dry filter it should lose a majority of its CO2 content (think of soda spilling onto the ground through porous material). So CO2 loss really depends on how much water is passing through the waterfall. 

I have used 2 bubbles per sec for my 55 g tank, and 3-4 for my 125g tank with inline CO2 reactors and no sumps. Its more cost effective for me to use the canister filter (inline reactor) method.  Then again, when you have multiple large tanks with CO2, saving $ on refills becomes that much more important compared with 1 or two tank setups that can afford to lose ~2 bubbles per sec (40-50% less efficient overall). 

In terms of efficiency, low flow tanks without a lot of water agitation that use a diffuser which gives off finely dissolve CO2 into the water and a solenoid/pH controller will retain the highest efficiency ratings (since tiny CO2 bubbles can't easily escape the water's surface like larger bubbles can - reducing the need for inputting more gas). Whew long sentence! 

But I'm sure sumps offer other perks, like ease of maintenance like you mentioned aquaman3000 and aesthetic appeal.


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