CO2 Scrubber Testing

[Rostato]

Interesting...I had the exact opposite happen to mine. Granted I wasn’t using outside air.

I’ve had new media since Tuesday and have barley seen that much media obsorbtion.

Question...why would you even use a co2 scrubber if you can use outside air anyway? I’d bet that if you ph dropped using your skimmer intake that you probably don’t even need the scrubber and can just use outside air.

 

[mitch91175]

Interesting...I had the exact opposite happen to mine. Granted I wasn’t using outside air.

I’ve had new media since Tuesday and have barley seen that much media obsorbtion.

Question...why would you even use a co2 scrubber if you can use outside air anyway? I’d bet that if you ph dropped using your skimmer intake that you probably don’t even need the scrubber and can just use outside air.

Wish I could use outside air, wouldn't even bother with the scrubber.

 

[ShadowR55]

I tried purely outside air and I was only getting a PH of 8

 

[Rostato]

I tried purely outside air and I was only getting a PH of 8

Just seems like you had exactly the opposite experience as everyone else when using the skimmer input.

 

[roberthu526]

Outside air is good enough for me. I don’t really pay attention to PH.

 

[ShadowR55]

Just seems like you had exactly the opposite experience as everyone else when using the skimmer input.

Yeah, I don’t know why, I plugged up all the other holes on the top of the skimmer cup lid. Does everyone else do that? The only thing I can think of is the humidity. I have dual Jumbo reactors so you would think PH shouldn’t be effected, maybe only how quick the media is used up.

 

[Rostato]

Outside air is good enough for me. I don’t really pay attention to PH.

Gee thanks for contributing to this thread :mad::mad:

Yeah, I don’t know why, I plugged up all the other holes on the top of the skimmer cup lid. Does everyone else do that? The only thing I can think of is the humidity. I have dual Jumbo reactors so you would think PH shouldn’t be effected, maybe only how quick the media is used up.

I left all other holes open. You maybe had too much moisture

 

[JDowns]

Yeah, I don’t know why, I plugged up all the other holes on the top of the skimmer cup lid. Does everyone else do that? The only thing I can think of is the humidity. I have dual Jumbo reactors so you would think PH shouldn’t be effected, maybe only how quick the media is used up.

I leave the vented holes open.

This will be one of the extended tests. I do think that if the air is oversaturated then condensation will form a vapor barrier on the media making it less effective. But thats why we test rather than speculate. First round started today. I'll update with photos tomorrow.

 

[ShadowR55]

I leave the vented holes open.

This will be one of the extended tests. I do think that if the air is oversaturated then condensation will form a vapor barrier on the media making it less effective. But thats why we test rather than speculate. First round started today. I'll update with photos tomorrow.

Awesome can’t wait to see the results.

 

[ShadowR55]

This is a picture of my scrubber yesterday after it ran 24hrs with outside air instead of skimmer air.

No more humidity in the chamber and my PH has gone up considerably, so I think humidity has to be kept below a certain level otherwise it seriously impacts scrubbing.

 

[JDowns]

This is a picture of my scrubber yesterday after it ran 24hrs with outside air instead of skimmer air.

No more humidity in the chamber and my PH has gone up considerably, so I think humidity has to be kept below a certain level otherwise it seriously impacts scrubbing.

This has been my observation during initial testing. That too much humidity negatively impacts performance. I'm excited to get that round of testing to see exactly what is happening with CO2 levels. I did rig up a pre scrubber using the nano scrubber from @BRS, but filled it with rice. This got rid of all of the condensation in the main scrubber and results....well got to wait for the real data.

 

[falc]

I am very interested in this subject to apply it in my own system but I am no expert! My understanding is that with C02 absorption media like soda lime there is a fine balance of humidity of the incoming air. Too little moisture of the incoming air will prevent the absorption process from being initiated, too much moisture in the incoming air will cause a blockage in the materials pore volume and decrease the absorption capacity. Also temperature will play a role since lower temperature air will decrease the moisture carrying capacity.

(Edit I found a reference that states incoming air should be maintained above 70%RH when using soda lime. Also the I read that the exothermic reaction should provide enough heat in a normal environment. ref. is the U.S. Navy design guidelines for C02 scrubbers 1985)

 

[JDowns]

Well.....first week testing was a bust. Some knucklehead forgot to disable the Automatic Background Logic. Normally this would be enabled as it allows the sensor to self calibrate and learn when CO2 levels are near ambient. In this situation when using two sensors that are calibrated and offset to each other, the sensor towards the skimmer inlet (INLET SENSOR) would constantly try and calibrate towards ambient due to very low CO2 levels. This caused the readings on the inlet over the week to drift upwards skewing the results.

Testing over the last two days shows data is good.

I’m pretty impressed with these sensors, while not cheap, are within 20ppm of a much more expensive lab device. And once calibrated within +- 10ppm of each other. My offset for the outlet sensor was 12ppm to match the inlet sensor at 400ppm reference gas.

So testing has now resumed.

 

[ShadowR55]

Where do you have the sensors? Is that Inlet of the scrubber and outlet of the scrubber?

 

[JDowns]

Where do you have the sensors? Is that Inlet of the scrubber and outlet of the scrubber?

Yes the sensors are the little blue boxes on the ends of the scrubber.

The inlet sensor connects to the skimmer, and the outlet sensor to fresh air, skimmer cup, or wherever. I really should have matched the names to the names on the scrubber port and not the skimmer itself. Oh well. I finished coding right after I had my tonsils out. So I blame the Oxy.

Either way CO2 levels are measured directly before or after each port on the scrubber itself.

 

[ShadowR55]

Ok, so the inlet as in inlet to the skimmer intake Venturi(and output of the C02 scrubber). And outlet is the input into the c02 scrubber correct?

I was thinking that the inlet would be inlet to the c02 scrubber and outlet would be the output from the c02 scrubber to the skimmer Venturi.

 

[JDowns]

Ok, so the inlet as in inlet to the skimmer intake Venturi(and output of the C02 scrubber). And outlet is the input into the c02 scrubber correct?

I was thinking that the inlet would be inlet to the c02 scrubber and outlet would be the output from the c02 scrubber to the skimmer Venturi.

Yes your thinking would have been much better. I'll transpose that when the data is presented. For some reason I was labeling based off of the skimmer. Inlet to skimmer and outlet to skimmer cup / fresh air. Next test I'll just swap the sensor locations and call it a day.

 

[ShadowR55]

Yes your thinking would have been much better. I'll transpose that when the data is presented. For some reason I was labeling based off of the skimmer. Inlet to skimmer and outlet to skimmer cup / fresh air. Next test I'll just swap the sensor locations and call it a day.

Use whatever is easier for you, as long as the data is presented properly everything should be fine. I just wanted to make sure I had it right as I follow along, can’t wait for the results!

 

[Reef man 89]

Well.....first week testing was a bust. Some knucklehead forgot to disable the Automatic Background Logic. Normally this would be enabled as it allows the sensor to self calibrate and learn when CO2 levels are near ambient. In this situation when using two sensors that are calibrated and offset to each other, the sensor towards the skimmer inlet (INLET SENSOR) would constantly try and calibrate towards ambient due to very low CO2 levels. This caused the readings on the inlet over the week to drift upwards skewing the results.

Testing over the last two days shows data is good.

I’m pretty impressed with these sensors, while not cheap, are within 20ppm of a much more expensive lab device. And once calibrated within +- 10ppm of each other. My offset for the outlet sensor was 12ppm to match the inlet sensor at 400ppm reference gas.

So testing has now resumed.

Where did you get that monitor? I have never seen that before

 

[JDowns]

Where did you get that monitor? I have never seen that before

It's custom made for this testing.