Outside air for skimmer. Expected results?

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kilnakorr

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I'm having some issues with low ph (7.6-7.7)
I figure the lockdown and cold weather is raising the CO2 levels in the house (4 persons inside 24/7, and to cold to open doors and windows.
I've just setup a test with the skimmer intake, getting fresh air through a small 'vent' at the window.
If the low ph is because of high co2 inside, how effective will the fresh air be? What increase should I expect? And how quickly will it rise?
I'm running a fairly small skimmer, skimz skimmate 7205 on a roughly 120 gl total water.
 
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kilnakorr

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I have high co2 inside my home and the outside airline seems to raise it about .3. Not sure how quick it was. I set it up long ago and think it was at least a day or two before retesting.
Thanks for reply. I know there's a lot of variables here, so a result from your own experience is very useful. I'll be happy with a 0.2+increase!
 

dwest

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I would guess a couple tenths also. But I think you might be only able to measure the difference with a pH probe.
 
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Hard to say. Some folks report quite positive results, others (including me) not. It would be interesting to understand under what conditions external air is effective.
 

Gtinnel

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I'll agree with others that it raised mine by a few tenths. I don't have a monitor to constantly check mine but every time I check it now it is between 8.2-8.4. I don't regret drilling the hole in the side of my house at all.

It seems like I remember someone mentioning a test you can do where you test a sample of water and then take it outside and test again to see what kind of difference it would make in your tank. Sorry I don't remember any details about how long the sample has to stay outside, or if you have to agitate the surface for the test however.
 

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Yes. It's been running around 7.8-8.0 for some time. Tank is just 2 months old, and ph began dropping a few days ago, when the diatoms went away. I guess they used up some of the CO2.

Great. Just watch how the min/max change over several days.

The pH drop when diatoms went away is probably because diatoms was doing the majority of photosynthesis in your tank. With it gone, rate of photosynthesis dropped substantially, less CO2 was consumed, thus pH dropped.
 

mdb_talon

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folks report quite positive results, others (including me) not. It would be interesting to understand under what conditions external air is effective.
The conditions are known and fairly straightforward. It works by introducing more oxygen into the tank. If your inside air has significantly higher co2 than outside air it can help (how much largely depends on skimmer). If your inside air and outside air are of similar co2 content then it will have little to no impact.
 
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kilnakorr

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I'll agree with others that it raised mine by a few tenths. I don't have a monitor to constantly check mine but every time I check it now it is between 8.2-8.4. I don't regret drilling the hole in the side of my house at all.

It seems like I remember someone mentioning a test you can do where you test a sample of water and then take it outside and test again to see what kind of difference it would make in your tank. Sorry I don't remember any details about how long the sample has to stay outside, or if you have to agitate the surface for the test however.
The problem with this test is outside temperature. Can't trust close to 0 degrees celsius water vs. 25 degree water.
 
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Have you thought about dosing kalk? I use a stirrer and dose every hour. Along with increasing pH, the benefits are: 1) Aids in supplementing alk and Ca, and 2) Aids in keeping water topped-up. I also run a Ca reactor, but often make small alk adjustments by making kalk dosing adjustments so I can leave the Ca reactor alone.
 
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kilnakorr

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The conditions are known and fairly straightforward. It works by introducing more oxygen into the tank. If your inside air has significantly higher co2 than outside air it can help (how much largely depends on skimmer). If your inside air and outside air are of similar co2 content then it will have little to no impact.
Yes. The amount of air the skimmer pulls, water volume, surface volume etc.
I'm well aware of how/why it works.
 

ca1ore

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The conditions are known and fairly straightforward. It works by introducing more oxygen into the tank. If your inside air has significantly higher co2 than outside air it can help (how much largely depends on skimmer). If your inside air and outside air are of similar co2 content then it will have little to no impact.

Well, I think its more complicated than that. FWIW it has nothing to do with introducing more oxygen. Mostly got it right after that.
 
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kilnakorr

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Have you thought about dosing kalk? I use a stirrer and dose every hour. Along with increasing pH, the benefits are: 1) Aids in supplementing alk and Ca, and 2) Aids in keeping water topped-up. I also run a Ca reactor, but often make small alk adjustments by making kalk dosing adjustments so I can leave the Ca reactor alone.
I only have a few corals, so continously dosing anything will eventually put Ca or alk higher than wanted.
 

mdb_talon

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Well, I think its more complicated than that. FWIW it has nothing to do with introducing more oxygen. Mostly got it right after that.

Pretty funny you say you dont know how it works then correct me lol. FYI when i mention oxygen it is related to the ratio of co2/oxygen levels in the air. So while technically high co2 is a depresser of ph introducing highly oxygenated air (ie less co2) drives ph up (assuming the tank has high co2 levels). And knowing the scenarios of when it works and why really is not that complicated. Even getting to the chemistry is not that complicated. As someone who knows very little about chemistry I manage to understand it.

Here is a good article. http://www.reefkeeping.com/issues/2004-09/rhf/
 
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