CO2 Scrubber Testing

[JDowns]

I'm going to let the first week testing run another day. I'm burning through the media pretty quickly with this test and the reduction percentage is really showing it the last two days. I want to let it run another day just to make sure its not an odd few days.

 

[JDowns]

First week of testing is complete. This was the dry test, where no added humidification was added. I allowed the test to run a few days longer since I started to see a drastic change in CO2 reduction from the media around day 7. As you can see after ten days the media is pretty well spent. It could probably run a bit longer but was starting to have an impact on my average PH.

I matched the PH data from APEX to the timeframe of the CO2 testing in a separate chart. You can easily see the swings throughout the day(s) when bodies start to pile into the office and the effects when everyone is gone for the holidays. You can see the CO2 reduction percentage starts around 60% and towards the end of the test is nearing 20%.

CO2 data is logged every 5 minutes where data is captured over a one minute timeframe 20 times (every 3 seconds), and then an average is created for each five minute interval. PH data is from APEX and is logged every 10 minutes.

Sensor have been re-calibrated to 400ppm gas, and the next test has started. The next test will be keeping RO water at the base of the CO2 scrubber to test the effectiveness of this method in adding humidity to the media.

If someone would like the raw data from the tests just let me know.

The spike in PH on the 19th at 08:40 is due to a manual dosing of 20ml of Two-Part ALK to raise Alkalinity to my desired target.

The random spikes on the 27th is most likely due to the traffic coming in and out the front door due to meetings all day. The tank is in our lobby area and has close proximity to the main conference room.

Edited to add 400ppm ambient line to chart.

 

[JDowns]

One last chart to show the decrease percentage between Inlet and Outlet.

 

[JDowns]

I think one thing that can be considered is skimmer size. I think we may be able to make an argument that using a skimmer that is larger than your systems needs, is needlessly adding CO2 to the system, and hampering higher PH levels if that is part of your goals for your system.

I was amazed today to see just how quickly PH rebounded and CO2 reduction once again went to the 60% range.

I'm curious to see if humidity levels increase CO2 percentage reduction and/or media longevity. I'm fairly positive from early testing prior to going live that media longevity will certainly increase or... maybe the humidity level plays into the coloration change being more pronounced.

Anyways....be fun to find out.

 

[ShadowR55]

Are you connecting it to the skimmer now?

 

[JDowns]

Are you connecting it to the skimmer now?

Next test that is running is with RO water at the base of the reactor, following BRS recommendation of (Add 1 Tbsp of RO/DI water to the bottom of the reactor body). Although I did add close to 100ml which is close to the base of the sponge without blocking flow or touching the media.

The next test will be connected back to the skimmer cup.

 

[2una]

I think one thing that can be considered is skimmer size. I think we may be able to make an argument that using a skimmer that is larger than your systems needs, is needlessly adding CO2 to the system, and hampering higher PH levels if that is part of your goals for your system.

I find the opposite but i run a calcium reactor so that's maybe why - i can drive my tank pH higher/lower just by increasing/decreasing skimmer pump power(DC Skimmer)

I actually suspect sps keepers & the theory of large skimmers being better is not really because it pulls more gunk but because it sits the pH higher

 

[JDowns]

I find the opposite but i run a calcium reactor so that's maybe why - i can drive my tank pH higher/lower just by increasing/decreasing skimmer pump power(DC Skimmer)

I actually suspect sps keepers & the theory of large skimmers being better is not really because it pulls more gunk but because it sits the pH higher

I could see that happening, if you are injecting CO2 for a calcium reactor increasing skimming may out-gas more of that concentrated CO2.

 

[JDowns]

I know individuals are interested to see the results from the test in which you recirculate from the skimmer. But I think I'm going to let each test run its course until the media at least starts to degrade to the point as the first test. I'm at the point with the second test, following the @BRS recommendation of RO water in the base of the reactor, as the first test and I'm not yet seeing the rapid decline in CO2 reduction. In fact I think we will see a slight increase in overall reduction and certainly an increase in longevity.

If the tests run too long I may just do interim updates so the graph charts aren't so huge.

As a side note, I started this back in early October with pre-testing and my ALK/CA usage has increased from 2800ml KALK, 20ml ALK/CA to 2800ml KALK to 50ml ALK/CA. This is in order to maintain my values at 8.5/450/1500. Right now Mag is manually maintained as I'm experimenting with something else there.

 

[ShadowR55]

I had a huge increase in ALK and CA consumption when I increased my PH as well. That’s why I hate it when people regurgitate the “don’t chase PH” mantra.

 

[JDowns]

I'll do a data dump this weekend but let test #2 run the course. I'm finally starting to see a change in the bottom 1/8th of the media to purple.

Still running at about 60% reduction, so no major changes there.

The jumbo canister will hold about 150ml of RO at the base without affecting air flow, and in my environment with ambient humidity at ~35% and air temp pretty steady at 72F doesn't need to be topped off but once a week.

 

[Epic Aquaculture]

This is great! I run a CO2 scrubber also so I'm following along.

 

[Rostato]

Just an FYI to add to one of my other posts. I run my co2 scrubber from my skimmer lid and I haven’t had to change my media since nov 6. I was steady around 8.31 to 8.42 The Whole time. Yesterday I noticed it peaked at 8.38 and a little color from the media, so maybe it’s finally exhausting.

I do have to remove the intake line and blow out water once a week. It seems to get a bit too much moisture built up in the lines every now and again. But it takes like 2 seconds to fix. I run silicon tubing so it doesn’t wear out from being removed from the barbed fitting.

 

[JDowns]

Test #2 is complete. I'll update this afternoon with the data.

 

[JDowns]

Just an FYI to add to one of my other posts. I run my co2 scrubber from my skimmer lid and I haven’t had to change my media since nov 6. I was steady around 8.31 to 8.42 The Whole time. Yesterday I noticed it peaked at 8.38 and a little color from the media, so maybe it’s finally exhausting.

I do have to remove the intake line and blow out water once a week. It seems to get a bit too much moisture built up in the lines every now and again. But it takes like 2 seconds to fix. I run silicon tubing so it doesn’t wear out from being removed from the barbed fitting.

Its usually that dip in PH or a dip in average PH that you start to see the media changing color. Depending on the size of the reactor and if you are adding humidification will determine how long it lasts. For the dry media, and the jumbo scrubber once I saw a dip in average PH it only lasted a few days. For the humid media, and the jumbo scrubber, the dip was drawn out and lasted another week. Best way to explain it would be that with dry media once the PH started dropping it fell off the cliff. For humid media it was a longer drawn out period of a very gradual fall off in PH.

I do like the idea of silicone tubing, or when I'm done testing is replace everything with quick disconnects. I'll need to re-print the enclosures for the CO2 sensors, but I'll wait until testing is done so all tests are done on the same environment.

 

[Rostato]

I had my dates wrong. I just checked my apex calendar. The media lasted exactly a month before I changed it. There was still some good media in the reactor but, I was only getting an average ph of around 8.3. I didn’t want to have to worry about overdosing my 2 part so I changed it. I’m running a stAndard size reactor on a Red Sea reefer 250

 

[JDowns]

I probably could have gone another 5-7 days with the media since it only showed about 75% change in coloration.

I only had to top off the water in the bottom of the reactor once a week, so from a maintenance standpoint that would be very acceptable on my end.

I can now explain some of the sharp blips in CO2 readings. I noticed that while I was working on the side of the tank where the CO2 scrubber was that just breathing close to the scrubber would result in a quick sharp increase in CO2 levels. So its no surprise that when folks are congregating in that area that there would be a correlating increase in CO2.

Adding humidity certainly increased the effectiveness and longevity of the media. Effectiveness can be seen as the higher decrease percentage and longevity has nearly doubled.

Also interested to note that while there was the typical drop-off in decrease percentage the media was still running efficiently enough to maintain a good pH level.

The odd flatline at the end of the PH graph was a water change.

Next test will be hooking up to the skimmer. The pH on this test may get skewed since I'm converting over to a refugium at night, but that won't effect the CO2 testing side since that is independent.

 

[JDowns]

I'm going to need to keep an eye on pH during this test and as the refugium comes on line. Starting the day at 8.33 is a bit of a new adventure.

 

[CNDReef]

That’s awesome info. Check your alk consumption as well. Wonder if after a certain threshold of ph it starts consuming more

 

[BestMomEver]

I think there is little question that CO2 scrubbers work. It is less clear that they impact pH in a consistently material way - some folks report significant increases, others not (I’m in that camp). Even if it does help to boost pH, does that translate to a healthier tank? I’ve seen no correlation of pH to tank ‘health’. Your test is cool, I’m just unconvinced that the effort to run and maintain a scrubber is worthwhile.

I’ve had a pH problem for a very long time. It always sat between 7.4 and 7.6. I’m not one to chase numbers, but I noticed my corals weren’t growing and their color was just average. I have lots of frags that stayed the same size for six months or longer.

I added a CO2 scrubber.... pH stays at a comfortable 8.3 now and my corals have taken off.... it’s crazy amazing. It was a minimal investment.... a $35 media reactor, a piece of tubing and $25 worth of media. Best mon y I’ve ever spent.