How to use co2 with sponge filters?

[Jacob Hill-Legion Aquatics]

I've planned my 40 gallon tank and I just need to gather the equipment and looking at all types of filtration the sponge filter gives me everything I want in a filter and its good for the guppies and shrimp I want to get.  I have a spare co2 system in storage from my last tank, can I use co2 with sponge filters? and what's the best way to diffuse it into the water? because sponge filters are lowflow and the fish I want don't like flow so I don't know how it would diffuse easily.  

[KBOzzie59]

I just use a diffuser.

https://www.aquariumcoop.com/collections/type_co2/products/aquario-neo-co2-diffuser

[nabokovfan87]

No matter what your filtration, you'd want to use a diffuser or reactor to get very fine bubbles.

[Melkor]

Try to find a powerhead that has adjustable flow. That is pretty much your best bet without a canister/HOB. Or you can adjust your BPS, but you will most likely use more co2.

[Jacob Hill-Legion Aquatics]

On 8/11/2022 at 6:33 PM, nabokovfan87 said:

No matter what your filtration, you'd want to use a diffuser or reactor to get very fine bubbles.

Yeah I have a good diffuser but wouldn’t I lose quite a bit of co2 from going to the surface?

[nabokovfan87]

On 8/11/2022 at 6:29 PM, Jacob Hill-Legion Aquatics said:

Yeah I have a good diffuser but wouldn’t I lose quite a bit of co2 from going to the surface?

CO2 has to be *very small* bubbles for it to dissolve into the water before it reaches the surface.  Your real issue is that you're going to be diffusing in CO2 and then the surface tension might actually release what you're trying to diffuse into the water.  Something I have been doing with the Kasa timers is turning off my airstone a bit before I diffuse my CO2, let the oxygenation drop, then diffuse in CO2.  Turn off the CO2, let that CO2 get used a little bit, then turn the Airstone back on.

If you're running 2 filters, maybe turn one off when you're diffusing CO2?  That might help.  Either way, I highly recommend getting a drop checker and using that.

[Jacob Hill-Legion Aquatics]

@nabokovfan87 k thanks for the help but doesn’t surface agitation also add oxygen and some co2 into the water so you’re not losing that much co2 plus if you want to see pearling plants you need so much oxygen in the water you can see the bubbles coming off the plants and it’s not just co2 that makes them pearl but tons of oxygen in the water. Also I have a drop checker already.

[nabokovfan87]

On 8/11/2022 at 7:09 PM, Jacob Hill-Legion Aquatics said:

@nabokovfan87 k thanks for the help but doesn’t surface agitation also add oxygen and some co2 into the water so you’re not losing that much co2 plus if you want to see pearling plants you need so much oxygen in the water you can see the bubbles coming off the plants and it’s not just co2 that makes them pearl but tons of oxygen in the water. Also I have a drop checker already.

Yes.  But the rate of surface tension might obscure (make useless) the adding of CO2 in the tank itself.  I use a drop checker and I prefer to track things that way.  I have ran tanks with CO2 with a ton of oxygenation.  Air does have CO2! So that helps a lot as well.  It's all just relative and you have to decide what is working, what isn't.

[Patrick_G]

On 8/11/2022 at 2:46 PM, Jacob Hill-Legion Aquatics said:

I've planned my 40 gallon tank and I just need to gather the equipment and looking at all types of filtration the sponge filter gives me everything I want in a filter and its good for the guppies and shrimp I want to get. 

This sponge filter should make good flow across the tank. You could easily modify an Aquarium Co-op filter to work like this one. 
 

AQUANEAT Sponge Filter, Corner Fish Tank Filter, for Breeding Shrimp Nano Fish Tank https://a.co/d/6fPaJBW

[Jacob Hill-Legion Aquatics]

On 8/11/2022 at 8:30 PM, nabokovfan87 said:

Yes.  But the rate of surface tension might obscure (make useless) the adding of CO2 in the tank itself.  I use a drop checker and I prefer to track things that way.  I have ran tanks with CO2 with a ton of oxygenation.  Air does have CO2! So that helps a lot as well.  It's all just relative and you have to decide what is working, what isn't.

what about a tank like this it has a sponge filter and co2 and the plants are pearling and doing amazing. (By: @Dean’s Fishroom)

Edited August 12, 2022 by Jacob Hill-Legion Aquatics

[nabokovfan87]

Correct. it's totally possible. Even my tank with CO2 has surface agitation.  If you're running excess filtration (2+ sponges, and an airstone, and a HoB, etc.) It might make sense to dial those back or to turn them off while dosing in CO2.

[Jacob Hill-Legion Aquatics]

@nabokovfan87so only running two sponge filters shouldn’t make me lose two much co2 correct? But I still will lose a bit because of the surface agitation.

[nabokovfan87]

On 8/12/2022 at 3:53 PM, Jacob Hill-Legion Aquatics said:

so only running two sponge filters shouldn’t make me lose two much co2 correct? But I still will lose a bit because of the surface agitation.

Right, you'll still lose "a bit" but I can't say how much that is.  Depends on which sponge filter, how much flow, the air pump, airstone, etc.  The best thing I can do is to recommend trying it, see what the drop checker says, watch the CO2 microbubbles from the diffuser and see how things run.  If you can't get it into the green, then you'll likely need to turn one off while running CO2 and then turn it on about an hour after CO2 finishes running for the day.

[Mmiller2001]

You actually want plenty of surface agitation. You want to off gass CO2 at a good rate and increase O2 in the tank. By off gassing CO2 at high rates, you will be able to push a faster rate of CO2. Which in return keeps more consistent CO2 levels. If off gassing CO2 is low, you have a higher chance of gassing your livestock. You also will have fluctuating CO2 with poor gass exchange. 

This explains it quite well with graphs.

https://www.2hraquarist.com/blogs/choosing-co2-why/how-to-push-the-limits-of-co2-safely

[Jacob Hill-Legion Aquatics]

@nabokovfan87@Mmiller2001 thanks guys for the help.