Recirculating C02 Scrubber question

reely989 · Feb 18, 2023

So I”m going to add a CO2 scrubber to bump my pH a bit. It’s not terrible, usually ranges from 7.9 to 8.1, but I’d like to get that a bit higher. I’ve read that setting up a scrubber in a recirculating fashion helps to raise pH more and makes the media last longer. I see attachments for skimmers, but it looks like I could easily DIY my skimmer cup but I just wanted to confirm. Could I essentially just drill my skimmer cup and fit a 3/8“ barb and run that to the scrubber input, and run the scrubber output into my skimmer as usual?

piranhaman00 · Feb 18, 2023

Yes, you need a float switch in the cup

reely989 · Feb 18, 2023

piranhaman00 said:
Yes, you need a float switch in the cup

To prevent foam from getting back into the scrubber right?

piranhaman00 · Feb 18, 2023

reely989 said:
To prevent foam from getting back into the scrubber right?

Sure but more importantly , not getting water from scrubber sucking into tank

Randy Holmes-Farley · Feb 19, 2023

I’m not a fan of fully recirculating a skimmer because it eliminates one of the advantages of a skimmer: oxygenation.

dadnjesse · Feb 19, 2023

A float switch is a good Idea. I run a co2 scrubber through my Life Reef Skimmer and went on vacation. The skimmer overflowed back into my Scrubber and into my tank. I came home to a Nuked Tank. I literally filled half of a Rubbermaid trash can with the dead Corals. Surprisingly my fish and Clam lived.

reely989 · Feb 19, 2023

Randy Holmes-Farley said:
I’m not a fan of fully recirculating a skimmer because it eliminates one of the advantages of a skimmer: oxygenation.

I was going to run a T to get some fresh air as well.

Lionfish hunter · Feb 19, 2023

reely989 said:
So I”m going to add a CO2 scrubber to bump my pH a bit. It’s not terrible, usually ranges from 7.9 to 8.1, but I’d like to get that a bit higher. I’ve read that setting up a scrubber in a recirculating fashion helps to raise pH more and makes the media last longer. I see attachments for skimmers, but it looks like I could easily DIY my skimmer cup but I just wanted to confirm. Could I essentially just drill my skimmer cup and fit a 3/8“ barb and run that to the scrubber input, and run the scrubber output into my skimmer as usual?

You could but with all the other holes in the skimmer lid, it won’t be as effective. I siliconed a piece of Tupperware over the lid of my skimmer and drilling a hole for the co2 scrubber. This lessens the chance of an overflowing skimmer ruining the tank and makes it a completely sealed co2 scrubber.

You will also likely need to add an air dryer so your media doesn’t get soaked. It is very simple. I used a simply lemonade bottle and it works great.

VikS · Feb 19, 2023

As others have said, seal the other holes in skimmer cup and leave just that one.

One more trick that worked is to add an empty canister before the scrubber. Collects all the water.

ptrick21186 · Feb 19, 2023

You could get another skimmer lid and silicone that one on top of the other one. Then put your barbed fitting into the top one. This will help reduce the possibility of foam getting into the scrubber. But in all honestly those pH numbers aren't bad. CO2 media only lasts like a week maybe 2 before it's exhausted (depending on ambient CO2 levels in your house). For the price you're gonna pay for media I'm not sure it's worth the minor results you'll see.

christwendt · Feb 19, 2023

I second I would into adding a moisture trap before the co2 scrubber. It’s another empty container to collect any water so media doesn’t get wet.

christwendt · Feb 19, 2023

christwendt said:
I second I would into adding a moisture trap before the co2 scrubber. It’s another empty container to collect any water so media doesn’t get wet.

Randy Holmes-Farley · Feb 19, 2023

reely989 said:
I was going to run a T to get some fresh air as well.

That should do the trick.

Lionfish hunter · Feb 19, 2023

ptrick21186 said:
You could get another skimmer lid and silicone that one on top of the other one. Then put your barbed fitting into the top one. This will help reduce the possibility of foam getting into the scrubber. But in all honestly those pH numbers aren't bad. CO2 media only lasts like a week maybe 2 before it's exhausted (depending on ambient CO2 levels in your house). For the price you're gonna pay for media I'm not sure it's worth the minor results you'll see.

My recirculating scrubber takes a few months to exhaust the media.

ptrick21186 · Feb 19, 2023

Lionfish hunter said:
My recirculating scrubber takes a few months to exhaust the media.

What is youre pH with and without the scrubber on? Honestly 1 month is pretty good! I wish mine was like that. What are the CO2 levels in your house?

dadnjesse · Feb 19, 2023

I use a double canaster the first one is empty to collect water and the second for the media.

Lbrdsoxfan · Feb 19, 2023

I gain approx .1-.2 overall. I use a smallish vessel to hold the soda ash so I have to replace it about every 2-4 weeks, I'm recirculating if it matters. You can see when it trended downward, the color was completely changed @ that point and it's trending back up.

Edit: my setup is diy and I also use a remote storage setup for the skimmer effluent so I don't worry about the cup overflowing. Also my lid is vented, I prefer some fresh air mixing in.

Steve2020 · Feb 19, 2023

reely989 said:
I was going to run a T to get some fresh air as well.

ptrick21186 said:
What is youre pH with and without the scrubber on? Honestly 1 month is pretty good! I wish mine was like that. What are the CO2 levels in your house?

People run a scrubber recirc in various ways. Some are successful and some are not as far as what PH people are trying to obtain. I modified mine a few times and I now have one that works great. It has increased my PH by >.4 and media last 6-8 weeks. PH would increase more if I didn't control it with my Profilux 4. Scrubber holds approx 12 cups of media.

Lionfish hunter · Feb 20, 2023

ptrick21186 said:
What is youre pH with and without the scrubber on? Honestly 1 month is pretty good! I wish mine was like that. What are the CO2 levels in your house?

It seems to be about a .2 difference max, nothing crazy. No co2 meter. 2 people in house so probably average.

reely989 · Feb 28, 2023

So to update this-- I ended up making a DIY recirculating scrubber from some cheap containers from the dollar store. I messed up a few fittings, but if you didn't mess it up, I think this whole project could have been done for 10 dollars. It's increased my pH by about .2-.25. I'm consistently hitting 8.32 during peaks, and my valleys are now 8.15 or so. It's been a very easy, affordable change. If anyone is interested in the setup, I'll post pictures.