9430 DC Skimmer Recirculating CO2 Scrubber?

[Tuffloud1]

I currently have an air pump pumping air through my CO2 scrubber and into the ozone inlet of my 9430 DC Skimmer. It works to raise my PH substantially however, I do go through a lot of soda lime faster than I’d like.

Is there a way to recirculate the scrubbed air so it isn’t just pumping air out to the ozone inlet but recirculates back through the scrubber?

 

[rvitko]

No, as the air vents from the large port on the side that is critical to the anti overfoaming feature. Generally, recirculating air from our experience also impedes skimming, this may not apply with a scrubber, but our general experience is that the decay products of skimmate result in bubbles that do not have the charge of normal air bubbles and do not attract proteins. We routinely study competitors products and we found that models that used the skimmer cup as a silencer and drew the air from the cup, performed rather poorly despite comparable specifications, it could be the scrubber media reduces this but this would also likely burn through the media, our assumption was methane and other decay gasses likely cause this effect. The best solution will be to use an air pump that is not so oversized that there is excess air going through, reduce the flow to just below what the skimmer can actually take in. Additionally, if you could place the air pump outside where there is less CO2, this can be for example above a soffit vent in the attic, on a covered porch, etc, you would reduce the CO2 coming into the scrubber.

 

[Tuffloud1]

No, as the air vents from the large port on the side that is critical to the anti overfoaming feature. Generally, recirculating air from our experience also impedes skimming, this may not apply with a scrubber, but our general experience is that the decay products of skimmate result in bubbles that do not have the charge of normal air bubbles and do not attract proteins. We routinely study competitors products and we found that models that used the skimmer cup as a silencer and drew the air from the cup, performed rather poorly despite comparable specifications, it could be the scrubber media reduces this but this would also likely burn through the media, our assumption was methane and other decay gasses likely cause this effect. The best solution will be to use an air pump that is not so oversized that there is excess air going through, reduce the flow to just below what the skimmer can actually take in. Additionally, if you could place the air pump outside where there is less CO2, this can be for example above a soffit vent in the attic, on a covered porch, etc, you would reduce the CO2 coming into the scrubber.

Thanks for the in depth explanation Roger!

 

[Chenko]

I just replaced my Tunze 9410 DC with 9430 DC on my 169g CADE system. I knew that trying to save $400 8 months ago will bite me... and I was right

However, like @Tuffloud1 , I want to use a CO2 Scrubber... and just ordered IceCap Large CO2 Protein Skimmer Air Scrubber.

Based on @rvitko reply above, it looks like recirculation would negatively impact Tunze's self correction/maintenance. Did I understand that correctly?

So I guess my question then becomes... Do I need to use an air pump? And if so, what would you recommend? And how would the diagram look? Pump to scrubber to ozone nozzle on 9430 DC?

Thanks,
Alex

 

[Tuffloud1]

I just replaced my Tunze 9410 DC with 9430 DC on my 169g CADE system. I knew that trying to save $400 8 months ago will bite me... and I was right

However, like @Tuffloud1 , I want to use a CO2 Scrubber... and just ordered IceCap Large CO2 Protein Skimmer Air Scrubber.

Based on @rvitko reply above, it looks like recirculation would negatively impact Tunze's self correction/maintenance. Did I understand that correctly?

So I guess my question then becomes... Do I need to use an air pump? And if so, what would you recommend? And how would the diagram look? Pump to scrubber to ozone nozzle on 9430 DC?

Thanks,
Alex

I have been running this one for 3 years.

Amazon.com

I have it in my equipment cabinet, running the inlet under the house through a crawl space vent and the output going through my CO2 scrubber. I am using a couple old rodi canisters for the CO2 scrubber. First canister I use to add moisture to the incoming air. I fill it with water once a week or so. The second canister I fill with soda lime. Pulling the outside air in helps the soda lime last longer. Then from that canister, the tube runs to a splitter which tees off into 2 smaller tubing runs. 1 connects to the skimmer and the other goes to a wood bubbler that I have in my sump overflow chamber.

My ph gets a boost of about .1 in the mild months (windows open more often) and .2 in times when my windows are shut more often.

 

[Chenko]

Thank you!

I like that the pump is real heavy duty. However, isn't 15LPM a bit of an overkill for just pushing air to the Skimmer? Also, do you have it running at all times? Do you regulate it at all?

What Soda Lime do you use? You mentioned that you go through it too quickly? What's quickly?

Thanks again!

 

[Chenko]

@Tuffloud1

 

[Tuffloud1]

Thank you!

I like that the pump is real heavy duty. However, isn't 15LPM a bit of an overkill for just pushing air to the Skimmer? Also, do you have it running at all times? Do you regulate it at all?

What Soda Lime do you use? You mentioned that you go through it too quickly? What's quickly?

Thanks again!

I run the pump 24/7 going on 4 years now with no issue at all. I put rubber feet under the feet that are installed on it and I can’t hear it in my equipment cabinet.

I go through 1 rodi canister full of soda lime per week.

I buy this big container of it and it lasts me months.

Jorgensen Laboratories JorVet Soda Lime, 5 Gallon | Med-Vet International

JorVet soda lime is a high-grade granular product that effectively absorbs carbon dioxide that is produced as an anesthesia by-product. It is a mixture of calcium hydroxide Ca(OH)2 also known as lime plus a smaller amount of sodium hydroxide NaOH. Upon exposure to carbon dioxide CO2, the calcium...

www.shopmedvet.com

 

[Chenko]

Thanks again @Tuffloud1 !

So you have AL-15A which is rated for 15LPM. Do you think that AL-6A which is rated for 10LPM would be sufficient? It draws 6 less Watts and is 2 dB quieter.

 

[Tuffloud1]

Yes, that would be fine. I got a higher rated one because my inlet run to the outside is pretty long (30 ft) so wanted to be sure it would be enough air flow without restriction. With that said, it ended up being more than enough pressure entering the skimmer chamber so I split it off and added an additional line going to the bubbler in the sump which cuts the amount of air going to the skimmer chamber by half. This matches well with the amount of intake air the Tunze pump pulls in. The bubbler just adds that much more CO2-free air going into the water.

My pump runs at 17watts continuous.

Thanks again @Tuffloud1 !

So you have AL-15A which is rated for 15LPM. Do you think that AL-6A which is rated for 10LPM would be sufficient? It draws 6 less Watts and is 2 dB quieter.

 

[Chenko]

Great.. thank you again!

 

[Tuffloud1]

Great.. thank you again!

One thing to keep in mind is that if you plan on having your inlet pull air inside your house, it will be very loud wherever the inlet tube end is. These pumps are loud unless you run the inlet tubing elsewhere.