Ph issues

anarchy · Aug 24, 2015

Randy Holmes-Farley said:
Local electrical issues can impact pH readings. Being near a lighting ballast, for example, can mess with some pH meters.

Yeah my ballast is pretty close to my sump but it's about equal distance from each probe

Randy Holmes-Farley · Aug 24, 2015

Try shutting off the light while watching the reading.

anarchy · Aug 24, 2015

Randy Holmes-Farley said:
Try shutting off the light while watching the reading.

neuwave · Aug 24, 2015

Downbeach said:
If you can get outside air to your skimmer, its unlikely you'll need the CO2 scrubber media(soda lime can be expensive). I would however consider using some GAC to keep any contaminants from entering your skimmer from the outside, i.e. insecticides, etc. You can use the same device, connect it the same way, just get the proper GAC as the media. I would also suggest you put some kind of filter/screen on the end of the pipe/tube you're using so small critters don't get into it and block the air flow. I used an old prefilter from a Maxijet on the end of my 1/2" vynil tubing.

CO2 exhausted quickly only if you don't use it correctly. Depending on the l/hr of air your skimmer takes in can impact the soda lime's exhaustion rate. For example I'm running a dual chamber (empty RO canister insert with cotton removed) CO2 reactor in series with a 300 l/hr air flow. If you are pulling more than 600 l/hr or more of air from your skimmer you may need larger canisters in series so you don't exhaust the media too fast. That's for a house with higher levels of CO2 such as Florida/Arizona or Maine/Alaska where the homes are shut tight.

Gac does absorb CO2 but not at the rate or volume soda lime does. You would need a much larger reactor and much more media to get similar results which increases the price. I've seen hobbyist try switch out the soda lime for Gac with little to zero impact.

Downbeach · Aug 25, 2015

The depletion rate of any CO2 absorbant(soda lime) will be proportional to the amount of CO2 that the air passing through it contains. So, obviously if you have a system that requires a larger skimmer drawing more l/hr air flow(mine was ~ 720l/h), the more air passes through it and the more CO2 has to be removed, the less time you will get out of the absorbant of the same quantity, the more frequently you will have to replace the media. I used a single canister I made up from an old RO unit, similar to the one BRS sells, and would get between 7 to 10 days of use out of each refill. If I used two in series, it stands to reason that I would get twice the use out of it, but would still remain proportional. Keep in mind that after the media is exhausted, and turns purple, it will turn white again, but will be exhausted.
The reason for the GAC wasn't to remove the CO2, but the possibility of other contaminants, i.e. insecticides,or other chemicals, that might be sprayed around the outside of the house.
I used to buy the Soda Lime in 5 gal. buckets through Med Vet. The cost was $87.00 and weight was 37lbs. This would yeild ~ 28 refills of the canister which would equate to about $2.35 per refill. If I bought the BRS media, a 9lb. container @ $50.00 with a yield of ~ 9 refills would equate to about $5.50 per refill.

Here's the canister:

shornik · Aug 25, 2015

ReefMadScientist said:
Yep. Tomorrow I get my CO2 scrubber in.

So I will be running it like this: Skimmer > CO2 Scrubber > Outside fresh air. (All connected by air line of course).

So I have a question, if we are running a line from the outside for fresh air, why the need for the CO2 scrubber? Wouldn't the CO2 scrubber only be needed if you are placing it between the skimmer and Inside air?

ReefMadScientist · Aug 25, 2015

shornik said:
So I have a question, if we are running a line from the outside for fresh air, why the need for the CO2 scrubber? Wouldn't the CO2 scrubber only be needed if you are placing it between the skimmer and Inside air?

You're exactly correct. When I ordered my CO2 scrubber I did not route my airline to the fresh air yet. I had no idea the good results I would see by doing this. So I no longer need my CO2 scrubber as I am at a very steady 8.0 pH.

So I have a brand new CO2 scrubber and media from BRS just sitting on my table....

shornik · Aug 25, 2015

ReefMadScientist said:
You're exactly correct. When I ordered my CO2 scrubber I did not route my airline to the fresh air yet. I had no idea the good results I would see by doing this. So I no longer need my CO2 scrubber as I am at a very steady 8.0 pH.

So I have a brand new CO2 scrubber and media from BRS just sitting on my table....

Could you put granulated carbon in it to remove any pollutants from the outside air or is this unnecessary as well?

Downbeach · Aug 25, 2015

shornik said:
Could you put granulated carbon in it to remove any pollutants from the outside air or is this unnecessary as well?

Not necessary, precautionary.

ReefMadScientist · Aug 25, 2015

I was thinking of just setting up the CO2 scrubber but I have a feeling its just useless in my non-situation. Hopefully someone is looking for one.

Randy Holmes-Farley · Aug 25, 2015

shornik said:
So I have a question, if we are running a line from the outside for fresh air, why the need for the CO2 scrubber? Wouldn't the CO2 scrubber only be needed if you are placing it between the skimmer and Inside air?

It would help reduce the CO2 further, but most people do not do both.

ReefMadScientist · Aug 25, 2015

Randy Holmes-Farley said:
It would help reduce the CO2 further, but most people do not do both.

Nice! Okay I will add it and post back the results.

neuwave · Aug 25, 2015

Downbeach said:
The depletion rate of any CO2 absorbant(soda lime) will be proportional to the amount of CO2 that the air passing through it contains. So, obviously if you have a system that requires a larger skimmer drawing more l/hr air flow(mine was ~ 720l/h), the more air passes through it and the more CO2 has to be removed, the less time you will get out of the absorbant of the same quantity, the more frequently you will have to replace the media. I used a single canister I made up from an old RO unit, similar to the one BRS sells, and would get between 7 to 10 days of use out of each refill. If I used two in series, it stands to reason that I would get twice the use out of it, but would still remain proportional. Keep in mind that after the media is exhausted, and turns purple, it will turn white again, but will be exhausted.
The reason for the GAC wasn't to remove the CO2, but the possibility of other contaminants, i.e. insecticides,or other chemicals, that might be sprayed around the outside of the house.
I used to buy the Soda Lime in 5 gal. buckets through Med Vet. The cost was $87.00 and weight was 37lbs. This would yeild ~ 28 refills of the canister which would equate to about $2.35 per refill. If I bought the BRS media, a 9lb. container @ $50.00 with a yield of ~ 9 refills would equate to about $5.50 per refill.

I use the same canister for my CO2 scrubber. I agree I would use Gac a precaution for pesticides and other such chemicals. I just got finished trying to explain the use of Gac as a CO2 absorbent substitute with local reefer I met at a lfs. He swore it would work just as good. Unfortunately it didn't have any impact on his PH using Gac compared to soda lime. I misread your post thinking you were trying to replace soda lime with Gac. I posted the importance of the air flow on a skimmer which is not posted on pre-made CO2 scrubber kits. I have been using a soda lime CO2 scrubber for 4 years now. I've changed skimmers from high air flow (Aquac ev180) to a low air flow(bubble magus 320 l/hr). When the larger skimmer had a single canister of soda lime on it the media would exhaust to a purple color in a matter of 3-4 days. Then two canisters were placed in series and had nearly the same exhaustion rate plus an extra day or two. Moved the same two canister in series and now they last about 16-17 days on average. I haven't done the calculation yet as I am waiting to get in touch with a professor of mine. But I want to calculate what the absorption rate of soda lime is while it collects CO2 as the air passes over it? Also what influences that absorption rate with higher air intake rates vs slower ones. Also comparing air volume passing over the media.
Anyway, say I bought your bucket of soda lime for $87. During this time frame I can get the 37lb bucket to last about one year. So per month I'm averaging ~ $7.25 to run the scrubber. I don't go by refill because the CO2 concentration in your home is always varying through out the year. Your assuming the CO2 concentration in your home remain constant and the number of refills are constant. So when people say it is expensive, at ~$7.25 a month is not too bad. I've seen hobbyist pay $50 in a few weeks just in buffers and additives.

Randy Holmes-Farley · Aug 25, 2015

neuwave said:
But I want to calculate what the absorption rate of soda lime is while it collects CO2 as the air passes over it? Also what influences that absorption rate with higher air intake rates vs slower ones. Also comparing air volume passing over the media.

I don't believe you'll be able to calculate the absorption. It is determined by the kinetics of the reaction, which is dependent on the solid surface area, temperature, humidity, the CO2 level itself, etc.

So IMO, it is measureable, but not calculable without extensive data that someone else has already generated on similar material.

Higher air flow rates will reduce the % CO2 eliminated from the air, but will increase the total CO2 removed over time.

Higher humidity should increase the % removed, but I'm not sure how big that factor is.