# CO2 bomb; how long?



## frogface (Feb 20, 2010)

I'll be CO2 bombing a few tanks this weekend (snails, ugh) and was wondering how long I need to leave the CO2 in the tank to kill off the snails. 

thanks

Here's a link to the awesome 'how to' posted by davecalk:
http://www.dendroboard.com/forum/care-sheets/57367-building-using-co2-generator-2.html#post497332


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## davecalk (Dec 17, 2008)

Frogface, Thank you for the kind words about my article.

The answer to your question depends on several factors.










The first factor has to do with the life cycle of the slugs.



*Slugs / Snails have an interesting lifecycle.
*

There are three stages in the life cycle of a slug / snail: the egg, the immature stage and the adult. An interesting point of note is that each life stage of these critters can survive through the cold winter without a problem. 

Now most Slugs and Snails are hermaphrodites having both male and female organs, so every individual can lay eggs and they can even self-fertilize. With this type of a system, you can raise a lot of slugs in a short period of time.









Garden Snails fertilizing each other.


These critters are so prolific that one individual has the potential to produce 40,000 or offspring throughout it's life, having up to 300 clutches, with 10 to 50 eggs per clutch. They prefer to deposit their eggs in moist, but not waterlogged areas. This is why they do so well in our tanks. They drop their eggs into any crack or crevice can find, hiding them under stones, sods of grass, attaching them to leaves, etc., any protected but moist place that they can find. We typically will only see 1 out of every 10 slugs that are in our tank. This is why the lettuce method of removing slugs tends to be so ineffective.

Their eggs look like little white / tan pearls, being gelatinous, and watery, usually spherical in shape, measuring about 3 - 4mm across. 












The development period of the eggs can vary greatly depending on the temperature and humidity. During warmer humid weather they can hatch as quickly as 10 days, just what they find in our little tropical islands of paradise. But when cooler conditions prevail maturation can take up to 100 days or more to complete. Also, eggs that are laid in the fall will typically survive the winter to hatch the following spring, just as soon as the weather warms back up.


During this stage of their life, a slug egg is much more resistant to hypoxia and suffocation. Therefore the CO2 bombing may not, likely will not kill all of the eggs. The higher levels of CO2 will slow down their development, but it seems that it will not kill all of the eggs without prolonged exposure to high levels of CO2. If you have plants in your tank this will be difficult to achieve.




*A Nuscince is Born*








After hatching the slug typically matures in less than a year, with most slugs taking about 5 months or so to reach adulthood. But if conditions aren't right it can take them up to 2 years to reach maturity. After puberty, they can live for two or more years as adults.











After each bombing, I leave the CO2 in the tanks over night with the glass lid left covering and closing off the tank. This will keep air currents and drafts from washing / blowing the CO2 out of the tank. Also plants love the high CO2 levels. In the presence of light, they will metabolize all of the CO2 they can get their leaves on. Therefore I turn the tank's lights off so that the plants photosynthesize less and which pulls out a lot less of the CO2 then if I leave the lights on.


Also a few folks who have experimented with CO2 have reported that only 8 out of 10 slugs and snails have actually been killed after a 24 hour exposure period to CO2. Therefore two out of ten slugs just might wake up from the CO2 kiss of death. 


All of these factors go into why I choose to bomb my tanks a second time the next day. That wayI figure I will kill any remaining adolescents and adult slugs. 

I found that even with bombing two days in a row, my tanks still had a few springtails that were likely to survive the bombing as I always have found a few springtails crawling around the tank the next day after the second bombing.


*Now to kill the Hatchlings*








I then wait a couple of weeks for any eggs to hatch out and then bomb the tank once more. This seemed to kill all of the slugs and slugs and snails, and the plants loved it too.




*Reseed the Tank*
Lastly I would reseed the tank with isopods and springtails, then put the frogs back into the tank.





*Happy hunting.*










Dave


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## mattolsen (Feb 26, 2009)

Having never done this before, and having some snail issues I have a couple questions for anyone who has some experience doing this. 

1) After bombing the tank how long should I let it air out before I put frogs back in?

2) I'm assuming that this method is going to kill all bugs, good and bad in the tank. How long should I wait to reseed the tank with isopods and springtails?


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## davecalk (Dec 17, 2008)

mattolsen said:


> Having never done this before, and having some snail issues I have a couple questions for anyone who has some experience doing this.
> 
> 1) After bombing the tank how long should I let it air out before I put frogs back in?



When done bombing for the last time let the tank sit for another 24 hours.

At the end of the 24 hour period blow into the tank with your breath, with a fan, whatever. The CO2 if there is any left will dissipate and be blown out of the tank. 





> 2) I'm assuming that this method is going to kill all bugs, good and bad in the tank. How long should I wait to reseed the tank with isopods and springtails?


You can now reseed the tank with your good bugs.


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## frogface (Feb 20, 2010)

Thank you!!


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## pdfDMD (May 9, 2009)

I put CO2 into one of my large tanks last summer to take care of snails and millipedes, and I really tried to suffocate everything crawling in it. After removing the frogs, of course, I sealed the tank and left the CO2 in for 24 hours. In my experience, it killed a majority of the pests but it did not kill every last one, snails included. Some of the millipedes that were motionless, seemingly snug in death's embrace, resurrected after a couple of days and I soon saw snails creeping along the glass as well. I did it twice with similar results; I believe that some of the critters were down in the soil and other areas that could harbor pockets of air while some others (the millipedes) were had a CO2 induced coma. After each session, I blew a fan into the tank for an hour or so and reintroduced the frogs with no trouble. It did kill a large number of pests, but it wasn't the kill-all I was hoping for.


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## earthfrog (May 18, 2008)

pdfDMD said:


> I put CO2 into one of my large tanks last summer to take care of snails and millipedes, and I really tried to suffocate everything crawling in it. After removing the frogs, of course, I sealed the tank and left the CO2 in for 24 hours. In my experience, it killed a majority of the pests but it did not kill every last one, snails included. Some of the millipedes that were motionless, seemingly snug in death's embrace, resurrected after a couple of days and I soon saw snails creeping along the glass as well. I did it twice with similar results; I believe that some of the critters were down in the soil and other areas that could harbor pockets of air while some others (the millipedes) were had a CO2 induced coma. After each session, I blew a fan into the tank for an hour or so and reintroduced the frogs with no trouble. It did kill a large number of pests, but it wasn't the kill-all I was hoping for.


If you have a drain tube that goes to the bottom of your tank, or the drilled hole itself, you can open it up, drain it out and in the false bottom area pump in the CO2. It will serve to push any air out of the substrate since it is heavier than the surrounding air. 
Also tightly seal the tank everywhere to keep as much CO2 in as possible during and after the bombing.


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## davecalk (Dec 17, 2008)

pdfDMD said:


> I put CO2 into one of my large tanks last summer to take care of snails and millipedes, and I really tried to suffocate everything crawling in it. .... It did kill a large number of pests, but it wasn't the kill-all I was hoping for.




It is possible that you had an air pocket that allowed the critters to live, but it is more likely that you had eggs that hatched later. Eggs are very resistant to CO2. You need to bomb later after any eggs could have hatched.


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## pdfDMD (May 9, 2009)

earthfrog said:


> If you have a drain tube that goes to the bottom of your tank, or the drilled hole itself, you can open it up, drain it out and in the false bottom area pump in the CO2. It will serve to push any air out of the substrate since it is heavier than the surrounding air.
> Also tightly seal the tank everywhere to keep as much CO2 in as possible during and after the bombing.


I failed to mention that I did have access to the false bottom and I dropped several chunks of dry ice into it with that goal in mind. Believe me, I taped the lid down well!




davecalk said:


> It is possible that you had an air pocket that allowed the critters to live, but it is more likely that you had eggs that hatched later. Eggs are very resistant to CO2. You need to bomb later after any eggs could have hatched.


Yes, I'm sure there were eggs and I had a feeling that many of them would be resistant to the treatment; it was a 55 gallon with plenty of hiding spots. After about one week, though, it was adult snails and millipedes that I saw both times, so some of them were able to survive somehow. In the end I tore it down and I'm in the process of rebuilding it.


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## davecalk (Dec 17, 2008)

pdfDMD said:


> I failed to mention that I did have access to the false bottom and I dropped several chunks of dry ice into it with that goal in mind. Believe me, I taped the lid down well!


Hmmm... Doctor, several questioned clicked when you posted. When you taped down the did you allow for some place for the air to get pushed out or was the lid taped down so well that the air gets trapped due to back pressure because it can't get displaced?

I am assuming that you bought a pound of dry ice. Did you use the entire pound in the tank? If so, that should produce about 250 liters or about 66 gallons of CO2. That should be plenty to completely displace all the air in the 55 gallon tank.




> Yes, I'm sure there were eggs and I had a feeling that many of them would be resistant to the treatment; it was a 55 gallon with plenty of hiding spots. After about one week, though, it was adult snails and millipedes that I saw both times, so some of them were able to survive somehow. In the end I tore it down and I'm in the process of rebuilding it.


Because some adults always seem to make it through the first bombing, I always recommend bombing at least three and possibly 4 times. 

Day 1 CO2 Bomb
Day 2 CO2 Bomb

Wait 2 to 3 weeks for any eggs to hatch.

Day 16 CO2 Bomb

Three times has seemed to work for me, but if you are really want to be sure.

Day 17 optional security CO2 Bomb


By the way, since when did dentists start working on frogs teeth? 


By the way, your post got me curious about the life cycles of millipedes and centipedes, and about the differences between the two, so I did a bit of digging. 

I started a new thread here.

Of Millipedes and Centipedes

One of the Millipedes might be usable as a food source.


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## davecalk (Dec 17, 2008)

pdfDMD your post got me thinking about how long it takes for Millepede and Centipede eggs to hatch and the info I found indicated that it can take several months for some species to hatch so a tank might need to be blasted a few months later, not just a few weeks.


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