Co2 scrubber with no airflow - help!

[GothFishKeeper]

My ph has been sitting at 7.6 both before and after installing the BRS co2 scrubber. I think the issue is that my skimmer doesn’t pull air fast enough for the scrubber to work. I feel no suction when I put my finger over the scrubber intake, and also when I do that the bubbles don’t stop going into the skimmer. My skimmer is the eshopps nano skimmer which has a 3/16" tube, but the scrubber uses a 3/8" tube. I connected them with an adapter. Do you think this is the issue? I'm attaching pics here as well. The only other issues I can think of wether they’re in combination with that or alone are that I have a 13.5g tank with a ton of surface agitation, and the top of my skimmer has four air holes in it because the way to adjust the skimmate level is moving the skimmer itself up and down. Any thoughts or solutions would be greatly appreciated, thank you!

 

[RoanokeReef]

Don't see any pictures but make sure you don't have the media packed to tight, especially since that's a smaller skimmer.

 

[jackson6745]

I get the same problem from my brs scrubber. I cut a piece of pvc to put inside of the media insert. What it does is raise the insert up 1/8” or so to allow for airflow. I’ll take a pic to show you what I mean. Easy fix

 

[Reef Outfit]

The Fluval EVO is an excellent nano tank. It was my first tank, and I kept it for a couple of years before (inevitably) upgrading to a larger setup. You can catch a glimpse of it here.

While I didn’t use a CO2 scrubber with it, I did create a tiny refugium to improve its performance, which you can check out here.

I initially used the Fluval skimmer for a while but eventually ran into some issues and decided to explore alternatives. After testing several brands, the AQUATICLIFE 115 Mini Internal Protein Skimmer/Filter for saltwater tanks up to 30 gallons was by FAR the best nano skimmer I found. I still use it in my quarantine tank (I’m not affiliated with it). Unfortunately, I can’t speak to the performance of the eShopps skimmer.

Regarding your issue, it's likely that "my skimmer doesn’t pull air fast enough for the scrubber to work" is correct. The small pump, narrow tubing, and skimmer design may not create enough vacuum force to effectively draw air through the scrubber. Additionally, increasing the tube dimensions can further reduce efficiency.

Another factor to consider is the height of the container. The taller it is, the more the media gets compacted by its own weight, similar to how water pressure increases with height. A wider container, instead of a taller one, would be more effective with a weaker vacuum. Alternatively, using less media could also help.

A smaller scrubber with more compact dimensions might work better in a small setup. I’d like to suggest a possible solution that could improve performance.

DIY Nano CO2 scrubber:

The first suggestion involves taping a thin layer of cotton or similar over the intake hole to prevent media from falling out. If that’s not feasible, you can consider the second option, which uses a design with small enough holes to retain the media while still allowing airflow. If your skimmer is still too weak to draw air, you could try the third option: using a small air pump to push air through the system, with a valve to adjust the flow and maintain the skimmer at the right level. If you have a controller you can set it to turn on/off according to your desired PH range.

 

[GothFishKeeper]

I get the same problem from my brs scrubber. I cut a piece of pvc to put inside of the media insert. What it does is raise the insert up 1/8” or so to allow for airflow. I’ll take a pic to show you what I mean. Easy fix

I’m a bit confused on what you mean by this. A picture would be appreciated because I’m willing to try anything at this point. Thank you

 

[jackson6745]

I’m a bit confused on what you mean by this. A picture would be appreciated because I’m willing to try anything at this point. Thank you

Sorr, forgot for about this. It’s just a little piece of 3/4” pvc that goes inside the concave area of the insert. That simply elevates the media insert from the plastic cylinder bottom to allow for airflow. Works perfectly.

 

[GothFishKeeper]

Sorr, forgot for about this. It’s just a little piece of 3/4” pvc that goes inside the concave area of the insert. That simply elevates the media insert from the plastic cylinder bottom to allow for airflow. Works perfectly.

Ah okay gotcha, thanks so much!!

 

[GothFishKeeper]

The Fluval EVO is an excellent nano tank. It was my first tank, and I kept it for a couple of years before (inevitably) upgrading to a larger setup. You can catch a glimpse of it here.

While I didn’t use a CO2 scrubber with it, I did create a tiny refugium to improve its performance, which you can check out here.

I initially used the Fluval skimmer for a while but eventually ran into some issues and decided to explore alternatives. After testing several brands, the AQUATICLIFE 115 Mini Internal Protein Skimmer/Filter for saltwater tanks up to 30 gallons was by FAR the best nano skimmer I found. I still use it in my quarantine tank (I’m not affiliated with it). Unfortunately, I can’t speak to the performance of the eShopps skimmer.

Regarding your issue, it's likely that "my skimmer doesn’t pull air fast enough for the scrubber to work" is correct. The small pump, narrow tubing, and skimmer design may not create enough vacuum force to effectively draw air through the scrubber. Additionally, increasing the tube dimensions can further reduce efficiency.

Another factor to consider is the height of the container. The taller it is, the more the media gets compacted by its own weight, similar to how water pressure increases with height. A wider container, instead of a taller one, would be more effective with a weaker vacuum. Alternatively, using less media could also help.

A smaller scrubber with more compact dimensions might work better in a small setup. I’d like to suggest a possible solution that could improve performance.

DIY Nano CO2 scrubber:

The first suggestion involves taping a thin layer of cotton or similar over the intake hole to prevent media from falling out. If that’s not feasible, you can consider the second option, which uses a design with small enough holes to retain the media while still allowing airflow. If your skimmer is still too weak to draw air, you could try the third option: using a small air pump to push air through the system, with a valve to adjust the flow and maintain the skimmer at the right level. If you have a controller you can set it to turn on/off according to your desired PH range.

Thank you so much for the detailed input, I really appreciate it.

I just removed about half of the media in the scrubber along with adding the extra foam piece that came with it to the bottom of the media chamber (on top of media when filling). Hopefully that does something.

I also utilized the third diagram you provided and attached an air pump to the intake side of the scrubber, which hopefully is making the air flow through it instead of having the pump pull stagnant air from the inside of the canister. If that doesn’t boost my ph within the next couple hours, I will most likely resort to the first or second diagram completely from scratch. Do you know if a kitchen tupperware will work as an airtight container? Or if it comes to that should I order something else online?