Why isn't my CO2 scrubber working?

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Calm Blue Ocean

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Pretty sure I know the answer but just in case I missed something I thought I'd ask my stupid question of the day.

First, I suspect it's either crappy skimmer or the water surface outcompeting the scrubber (which could go back to crappy skimmer).

Equipment: IM NuvoSkim Midsize skimmer + NLF PhosBan 150 reactor with TLF media changed 3 days ago. Measured pH with Apex and Hanna. IM 50g Lagoon AIO tank about 14 months old.

co2.jpg


Things I've tried: Shortened the connection between the skimmer and reactor (it's attached right where the silencer would go on the skimmer). Put a tablespoon of water in the bottom of the reactor.

pH rises if I open the window next to the tank but that's just not practical.

Media never seems to change color. Is it possible I got a bad batch?

I previously tried the small IceCap CO2 scrubber with no luck and switched to the reactor since it has a larger air intake (thought that might make a difference). Air is definitely going through, I can hear the pump sound change if I cover the intake and it's skimming.

Seriously, sometimes it seems like it's made things even marginally worse but it's hard to tell since I get fairly large pH swings.

Without any intervention (bathroom exhaust fan, open window) I get a range of about 7.6 to 7.8. With the window open I get closer to 7.8 to 8.0 so CO2 would seem to be the issue. So why is a scrubber not helping?

Anything I've missed in my setup?
 
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Calm Blue Ocean

Calm Blue Ocean

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While you hear air passing, is the air moving through the media?
You may need an in-line air pump which will pull a greater volume of air through the media for scrub.

As far as I can tell the air is moving through the media. I've looked for air leaks and nothing seems obvious. An air pump is on the list for "next thing to try" before winter hits and open windows won't be happening.

Any tips on sizing a helper air pump?
 

Uncle99

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I use a 125gph air pump to draw air, from the outside, 6 feet away and into the skimmer.

It was to far away for natural Venturi pull by the skimmer.

I was just wondering if the CO2 air is too slow, or is sidestreaming (air going over just the top media, or up the sides of the canister. Moving more air will decrease that, it’s all about contact with any media.

I would also mention that the measurement at best of PH with hobby grade tests is mostly inaccurate and your measured amount, may differ from actual. My so called 7.9 was 8.2 per ICP.

Maximize surface movement, pull and/or scrub incoming air of CO2, if you 2-part dose, dose Alk during lights out, blow a fan across the surface after lights out will all contribute to a more stable PH, not necessarily the highest PH.
 
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Calm Blue Ocean

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I use a 125gph air pump to draw air, from the outside, 6 feet away and into the skimmer.

It was to far away for natural Venturi pull by the skimmer.

I was just wondering if the CO2 air is too slow, or is sidestreaming (air going over just the top media, or up the sides of the canister. Moving more air will decrease that, it’s all about contact with any media.

I would also mention that the measurement at best of PH with hobby grade tests is mostly inaccurate and your measured amount, may differ from actual. My so called 7.9 was 8.2 per ICP.

Maximize surface movement, pull and/or scrub incoming air of CO2, if you 2-part dose, dose Alk during lights out, blow a fan across the surface after lights out will all contribute to a more stable PH, not necessarily the highest PH.

Thanks for giving my setup a sanity check. I'll take it apart again and make sure everything is fitting securely and air is taking the path it's supposed to (in through the top, down the tube in the center, back up through the media to the skimmer intake). An air pump is probably the smartest solution (if the rest of the equipment checks out) since like you said, it would also allow me to pull air from outside and improve things that much more. I'll give a fan across the water surface a shot as well. Of course, another pH check might also save me all of this trouble! lol
 
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DrMMI

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I'm having the exact same problem. pH ranges from 7.55 to 7.7 at best. Goes up to 7.9 with windows open. I'm also dosing kalk throughout the day and it doesn't help much. With regards to the air pump, are you connecting it to the CO2 scrubber intake? How do you do that since the airpump uses 1/4" airline tubing and the scrubber intake is 1/2"?
 
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Calm Blue Ocean

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I'm having the exact same problem. pH ranges from 7.55 to 7.7 at best. Goes up to 7.9 with windows open. I'm also dosing kalk throughout the day and it doesn't help much. With regards to the air pump, are you connecting it to the CO2 scrubber intake? How do you do that since the airpump uses 1/4" airline tubing and the scrubber intake is 1/2"?

Funny you should ask because I've seen a number of people mention using air pumps to help push/pull air but haven't been able to find a single picture or detailed description of how they are hooked up. Would you even make it air tight or would you set it up so that the air pump just added to the air that was being drawn in by the skimmer? All the same, I just ordered some reducers and a Y connector so I can play around with some ideas.
 

DrMMI

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So last night I cleaned out my skimmer and hooked the co2 scrubber back up. I have two scrubbers in daisy chain for my 260g. Before connecting the tube from the skimmer cup to the air intake to recirculate the air, I noticed that there wasn't much suction on the air intake side. I took off the second scrubber and just left the one. This is what my pH did overnight. So I think my issue was that my skimmer isn't strong enough to pull air through two scrubbers.
 

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jda

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Double and triple check your probes - they are cheap, drift and fail often. pH pen can be more accurate.

You need to air out your house. Nothing will have the affect that this does. Find a cool time and do it... night or right when the sun is up can work.. like 05-06:00. In the winter, then 3-4 PM is best when it is warmest. If you think that this is not practical, neither is replacing soda lime all of the time. At some point, a scrubber cannot overcome so much co2 in the ambient air... it only removes some of it, not all... so the more that you have, the more that you have after the scrubber soaks some up... and it won't last as long.

What are we talking like 2 hours of windows open and fans in the windows? Even if the temp rises 2-4 degrees and the AC runs for 15 more minutes, this is a few bucks a week? How much is soda lime and a reactor? I honestly don't know the answer, so just asking.

Outside air line to the skimmer can help some, but still not as much as airing out the house. We run an attic fan every night from the spring to fall and once or twice a week for an hour on a nice Winter day - be sure to get all of the levels including any basement.

More than just the tank benefits from the fresh air... turns out humans and pets can benefit a lot too.
 
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Calm Blue Ocean

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Double and triple check your probes - they are cheap, drift and fail often. pH pen can be more accurate.

You need to air out your house. Nothing will have the affect that this does. Find a cool time and do it... night or right when the sun is up can work.. like 05-06:00. In the winter, then 3-4 PM is best when it is warmest. If you think that this is not practical, neither is replacing soda lime all of the time. At some point, a scrubber cannot overcome so much co2 in the ambient air... it only removes some of it, not all... so the more that you have, the more that you have after the scrubber soaks some up... and it won't last as long.

What are we talking like 2 hours of windows open and fans in the windows? Even if the temp rises 2-4 degrees and the AC runs for 15 more minutes, this is a few bucks a week? How much is soda lime and a reactor? I honestly don't know the answer, so just asking.

Outside air line to the skimmer can help some, but still not as much as airing out the house. We run an attic fan every night from the spring to fall and once or twice a week for an hour on a nice Winter day - be sure to get all of the levels including any basement.

More than just the tank benefits from the fresh air... turns out humans and pets can benefit a lot too.

I agree about fresh air and have been opening a window every night to moderate CO2. Simple and low tech. However when winter hits I'd still argue that open windows can stop being practical. We had days just this past February with daytime highs in the negative double digits (F), and I'd call last winter unusually mild . It would be nice to find a working solution when the cheaper, easier, and more obvious ones are not practical. At some point I expect my tank will cross a threshold of coral growth where we'll start seeing some appreciable alk consumption and something like kalk might become a viable option. But for now, we band aid things to fill the gaps.

Just rechecked the probe and it seems correct. The home is just 8 years old with all gas appliances. Definitely examining all solutions but it would be nice to be able to just slap the CO2 scrubber on when needed.
 

jda

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I know that there are many Colder places on the earth, but I live in Colorado and I can find a day every few weeks to get some fresh air in. On a really bad stretch, maybe it takes a third week, but even 40 degrees and sunny is an open window day for us and everybody can tell a difference. We only keep the house near 60 degrees, so it doesn't take long to heat the house back up and if the sun is out, the furnace does not even run.

I know that this is not routine or easy and that it takes work to plan it out and find a day, but it takes more work to make a co2 srubber work in a house with no fresh air.
 
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