THE BEST WAY to implement a CO2 scrubber!

[Michael Hull]

Man I have my CO2 Scrubber hooked to the intake on my skimmer and I still can't hit over 8.0. I must be doing something wrong.

Do you have humid air running through the scrubber? or at least a little water in the bottom of the scrubber?

 

[TheKingInYellow]

Yes, a little water in the scrubber and I draw air from right in the sump.

I am going to try pulling fresh air instead.

 

[saul831]

At first I thought of setting up a bypass with a solenoid and controlling this through an Apex outlet, but the problem with using a solenoid here is that the open and closed durations are long and of similar length; so any solenoid would need to be energized (and getting hot) for far longer than I would consider safe.

I ordered the Solenoid Valve with Push-to-Connect Fittings, 24V DC. from McMaster-Carr.
I did noticed that when i applied 24V it did get really hot, so I decreased the voltage until the Solenoid Valve closed. In my case the valve seamed to work with only 12.5V, less voltage means less heat.
I am now running the Solenoid Valve and there is now not even warm to the touch. Just to be sure, i did install a small fan that cools it when the Solenoid Valve is energized.

 

[Reefahholic]

IMO, a solenoid valve restricts too much flow. I've used both and electric ball valves are much better. Highly recommend them.

 

[Maxx]

Autoaqua Smart Skimmer Security will do the trick if you are concerned about that.

Thanks for this suggestion.
I've been trying to find a way to do exactly this without currently owning an Apex.
Apex is on the list, but I cant do it right now.
This is brilliant.

 

[iReefer12]

I implemented this a couple of days ago and I have a couple of questions. I am using a Vertex Alpha 200 skimmer, and the BRS Co2 scrubber.

1. The Vertex skimmer cup has 4 vent holes in the top. Right now the intake for the Co2 scrubber is connected to 1 of these vent holes. Should I find a way to block off the other 3 vent holes or possibly T the intake line to all 4 vent holes?

2. I have quite a bit of moisture building up inside the canister. I’m wondering if I drill and tap the bottom of the canister, can I install a drain, possibly drain down to a mason jar to collect there? Would this work?

 

[Vin's Reef]

I implemented this a couple of days ago and I have a couple of questions. I am using a Vertex Alpha 200 skimmer, and the BRS Co2 scrubber.

1. The Vertex skimmer cup has 4 vent holes in the top. Right now the intake for the Co2 scrubber is connected to 1 of these vent holes. Should I find a way to block off the other 3 vent holes or possibly T the intake line to all 4 vent holes?

2. I have quite a bit of moisture building up inside the canister. I’m wondering if I drill and tap the bottom of the canister, can I install a drain, possibly drain down to a mason jar to collect there? Would this work?

I don’t think you need to block the other vent holes since there is a plenty amount of moisture to wet the CO2 media. U may want to put a solenoid valve there with a Tee barb connector so you can activate the “wet” air when the pH is below what you want it to be. Just an extra measure to keep pH stable and avoid spikes.

 

[Saltyanimals]

I implemented this a couple of days ago and I have a couple of questions. I am using a Vertex Alpha 200 skimmer, and the BRS Co2 scrubber.

1. The Vertex skimmer cup has 4 vent holes in the top. Right now the intake for the Co2 scrubber is connected to 1 of these vent holes. Should I find a way to block off the other 3 vent holes or possibly T the intake line to all 4 vent holes?

2. I have quite a bit of moisture building up inside the canister. I’m wondering if I drill and tap the bottom of the canister, can I install a drain, possibly drain down to a mason jar to collect there? Would this work?

Heading into the scrubber solution now and this is a very good thread. Thank you everyone for sharing.

Questions:

I had the same question looking at some of the pictures here. Many of us have holes already on the skimmer lid, but then I see folks drilling an additional hole. Not sure why except maybe it looks more finished? I could easily just stick a 1/4 right into one of the holes and leave the others alone and add zero additional effort. I'm assuming these additional holes are for the back pressure and maybe to vent the humidity that might be in the cup so prob not a good idea to cover the remaining holes.

I'm also questioning the solenoid effort. Someone earlier raised a very simply solution if you have it Apex monitored. = if tank pH > 8.3 Skimmer OFF. I agree skimmer off for a bit won't hurt anything as most of us don't actually need it on 24/7. Can anyone think of disadvantages of this simple solution?

 

[esquare]

Awesome thread!
My question deals with air/gas exchange. I've always heard that the skimmer is the main source of gas exchange so will recirculating the air the skimmer draws impact the gas exchange?

If so, would running the scrubber input air through the head space (so the lines are not submerged) of your RO/DI reservoir address the moist source air issue while not having to refill a jar with water or the bottom of the scrubber with water? The input air could then draw from the room to the ro/di reservoir or from the outside (preferably outside to cut down on the co2 needed to be removed.

I also like the auto ball valve idea to actually control the ph level.

 

[Maxx]

No issues with gas exchange here.
The bigger issue IMO is that you're adding an extra unnecessary step that doesnt improve the process.

 

[stevenfreeves]

It totally does!

how does air get into the mason jar? seems like you would need and input and output for the air right?

 

[TheLost]

Heading into the scrubber solution now and this is a very good thread. Thank you everyone for sharing.

Questions:

I had the same question looking at some of the pictures here. Many of us have holes already on the skimmer lid, but then I see folks drilling an additional hole. Not sure why except maybe it looks more finished? I could easily just stick a 1/4 right into one of the holes and leave the others alone and add zero additional effort. I'm assuming these additional holes are for the back pressure and maybe to vent the humidity that might be in the cup so prob not a good idea to cover the remaining holes.

I just built a 'cap' that goes over my skimmer lid

• Covers all the holes
• Doesn't require drilling into the skimmer or lid
• Reduces the chance of foam getting into the scrubber

 

[Saltyanimals]

I just built a 'cap' that goes over my skimmer lid

• Covers all the holes
• Doesn't require drilling into the skimmer or lid
• Reduces the chance of foam getting into the scrubber

Awesome cap idea. I was thinking about something similar that I could 3D print, but was thinking about some kind of plastic extension to connect to ONE of the holes on the cup lid which would give some water vacuum protection. The cap sounds great because the height gives enough room for it to foam over without getting sucked in. i.e. increase the thickness/height to give even more room as needed.

Have you seen the performance of the skimmer change going from multiple holes in the original lid.. and down to one single one?

My alternative which is probably easier is using the on-cup waste drain line, but what would require another collection reservoir to add to the sump which is already tight for me. Your cup idea might save me another gadget to put into the sump.

 

[TheLost]

Awesome cap idea. I was thinking about something similar that I could 3D print, but was thinking about some kind of plastic extension to connect to ONE of the holes on the cup lid which would give some water vacuum protection. The cap sounds great because the height gives enough room for it to foam over without getting sucked in. i.e. increase the thickness/height to give even more room as needed.

Have you seen the performance of the skimmer change going from multiple holes in the original lid.. and down to one single one?

My alternative which is probably easier is using the on-cup waste drain line, but what would require another collection reservoir to add to the sump which is already tight for me. Your cup idea might save me another gadget to put into the sump.

My first design was a smaller 'cap' that clipped into the center of the lid leaving the outside holes open. I ran it for about a week.. but over time i noticed it was causing an issue due to the way it was pulling air from the center where all the bubbles/foam hit the skimmer lid.

My tank (reefer 350) is in my den, and since I've been working from home my pH has consistently been in the low 7.8 - 7.6 range. It is not happy having me and my 2 English bulldogs spend ~10 hours a day in the same room with it.

One bag of C02 media would last just a few days.

So my #1 goal was to raise pH and not end up in the poor house by spending $$$ on soda-lime every month

With the new 'full cover cap' i have more control over what 'outside' air gets into the system. using a manual ball valve I can keep the pH in the 8.4 range (i top out around 8.5 right when my lights turn off). My Apex will alert me if it gets higher and shut down the skimmer.

I haven't noticed any change in the amount of skimmate the skimmer is making (with the larger cap)

After 14 days my CO2 media is still going strong. I would like to get 4 weeks per canister (~$5 per month).

One unplanned side-effect is that the tank holds its temperature better. I assume it because the air being recycled is the same temperature as the tank, where before it was sucking in the colder A/C cooled room air. Looking at the power chart on the Apex my heater usage watts are lower this week with the larger lid.

 

[Randy Holmes-Farley Verified Community Expert]

IMO, recycling the skimmer air is a bad idea, at least if it is the majority of air going back into the skimmer.

It eliminates what i consider to be one of the biggest benefits of a skimmer: oxygenation.

 

[TheLost]

IMO, recycling the skimmer air is a bad idea, at least if it is the majority of air going back into the skimmer.

It eliminates what i consider to be one of the biggest benefits of a skimmer: oxygenation.

Correct me if I'm wrong... but the skimmer is still putting oxygen into the tank. If anything, its CLEANER O2 because the air has been run through the CO2 scrubber more times than NOT recirculating the air.

Also.. a pH of 7.7 has had a devastating effect on my tank.

In the two weeks I've been running the recirculating C02 scrubber the Alkalinity consumption in my tank has skyrocketed, My corals appear to be doing better, and coralline algae is growing on my glass again.

 

[Randy Holmes-Farley Verified Community Expert]

Correct me if I'm wrong... but the skimmer is still putting oxygen into the tank. If anything, its CLEANER O2 because the air has been run through the CO2 scrubber more times than NOT recirculating the air.

Also.. a pH of 7.7 has had a devastating effect on my tank.

In the two weeks I've been running the recirculating C02 scrubber the Alkalinity consumption in my tank has skyrocketed, My corals appear to be doing better, and coralline algae is growing on my glass again.

I'm not by any means saying it is not desirable to raise pH that is 7.7. I would raise it. That has nothing whatsoever to do with O2.

If all the air run through the skimmer is recycled over and over, how could the skimmer possibly add O2 to the tank? Where would it come from?

Reducing CO2 in the air does not increase the O2 content in the air by any significant extent.

As for folks claiming they have plenty of other aeration, they may need to think again. Only a reef tank that showed zero pH swing day to night can claim perfect aeration. many reef tanks become O2 deficient at night, and I personally would run a skimmer even if it did nothing but aerate the water.

 

[TheLost]

I'm not by any means saying it is not desirable to raise pH that is 7.7. I would raise it. That has nothing whatsoever to do with O2.

If all the air run through the skimmer is recycled over and over, how could the skimmer possibly add O2 to the tank? Where would it come from?

Reducing CO2 in the air does not increase the O2 content in the air by any significant extent.

As for folks claiming they have plenty of other aeration, they may need to think again. Only a reef tank that showed zero pH swing day to night can claim perfect aeration. many reef tanks become O2 deficient at night, and I personally would run a skimmer even if it did nothing but aerate the water.

It's almost the exact same principle as a scuba rebreather.

In this case, It's not a sealed system... outside air gets added into the skimmer but at a slower rate.

100% of the air sucked into the skimmer does not get added to the water. Re-using that CO2 clean air reduces the rate that the CO2 scrubbing media is used, by adding in a controlled amount of 'dirty' outside air you can 'dial in' the exact pH you want (i can get my pH higher than 8.5.. but i keep it at 8.4).. and it has the added benefit replacing O2 in the loop.

BRS has talked about this a bunch.

This thread is ~4 years old.

 

[Randy Holmes-Farley Verified Community Expert]

It's almost the exact same principle as a scuba rebreather.

In this case, It's not a sealed system... outside air gets added into the skimmer but at a slower rate.

100% of the air sucked into the skimmer does not get added to the water. Re-using that CO2 clean air reduces the rate that the CO2 scrubbing media is used, by adding in a controlled amount of 'dirty' outside air you can 'dial in' the exact pH you want (i can get my pH higher than 8.5.. but i keep it at 8.4).. and it has the added benefit replacing O2 in the loop.

BRS has talked about this a bunch.

This thread is ~4 years old.

Of course the recycle method reduces the consumption of media. That's not my point. Reduced oxygenation is the point. That is why I do not recommend it.

If you use partly fresh air, and partly recycled air (that will have low O2 whenever the tank water is low in O2) then you have partly solved the problem of low O2, and partly not.

if you completely use fresh air, then you have completely solved the Low O2 in the air problem.

Measuring O2 is expensive. Measuring CO2/pH pH is easy. few people measure O2, and many measure pH.

Does that make pH more important than O2?

I suggest that folks thinking recycling air is a good idea and don't pay attention to O2 might want to read some of Eric Borneman's O2 articles. They have some issues, but the point is clear: reef tanks often drop below O2 saturation at night, and skimmers are a good way to raise the O2.

http://www.reefkeeping.com/issues/2005-06/eb/index.php

http://reefkeeping.com/issues/2005-07/eb/index.php

http://reefkeeping.com/issues/2005-08/eb/index.php

" Aquaria can and do become hypoxic at night and such a state may pose a risk to hypoxia-intolerant organisms. "
" Airstones and skimmers appear to be a very effective means of oxygenating small water volumes. "

 

[TheLost]

I suggest that folks thinking recycling air is a good idea and don't pay attention to O2 might want to read some of Eric Borneman's O2 articles. They have some issues, but the point is clear: reef tanks often drop below O2 saturation at night, and skimmers are a good way to raise the O2.

My skimmer is running at night. Outside air is still added to the skimmer

Its been ~30 years since my chemistry days in college.. but if all of the O2 was depleted in the system the skimmer would be less efficient, fewer bubbles would be produced, and eventually, a vacuum would be formed due to the missing the oxygen...

but again... it's not a sealed system.. Outside air is used. The skimmer is working exactly the same as before (same skimmate produced, same bubble levels, same power consmption.. etc)

Unless you can show that a skimmer uses 100% of the air sucked into the venturi I don't think I have anything to worry about. If anything my skimmer is adding more PURE O2 into the tank than before at night.