Outdoor CO2

[Scubajoe1]

So I was curious if anyone has taken a look at the affect of removing the CO2 from the air outside by passing the skimmer intake line through a CO2 scavenger. I know that a solution to increase pH is to run the line outside to use outside air but that still has 350-450 ppm CO2. Indoor levels cannot be crazy high because above 1000 ppm- 2500ppm you get to feeling drowsy. I don't think my CO2 indoors has ever been that high. If it's beneficial to say use air that is 400 ppm vs 800 ppm would you not get additional benefit by using air that is 0 ppm CO2?

Just curious.

Scubajoe

 

[rwb500]

lots of people use a co2 scrubber. search for it.

 

[bertoni]

If the tank is getting too much carbon dioxide, scrubbing the outside air might help. I don't think it's very likely to cause a problem, either, so it might be worth trying. In theory, you might want to watch for signs of the pH rising too much, but I think that's unlikely.

 

[Scubajoe1]

I ordered scrubbing soda lime today and a Universal air filter. Will update with success or lack of next week.

 

[tmz]

I agree with Jonathan. Just watch the pH in case the scrubber over does it. I use mine with indoor air and discontinue it seasonally when pH drifts high. I'd also watch air intake to the skimmer ;a run to outside air and/or a scrubber depending on how they're made might restrict it .

 

[bertoni]

Interesting. How high does the pH get before you discontinue the scrubbing?

 

[tmz]

8.4 diurnal highs or so; never 8.5. I prefer to keep it in the 8.15 to 8.35 daily range. I have a large house with just my wife an I and 2 dogs here most of the time now that the kids are grown. In the winter the relative humidity drops to around 20% in the heated basement where much of the system is. When it goes down like that the pH climbs .Boomer once explained that as having something to do with mist gathering and dumping some CO2,IIRC. . I also dose limewater for top off 24/7 but at a constant level of 16 liters per day for the 650 gallons of water , regardless of evaporation. At that rate with sg at 1.026, alk is steady at 160 to 165 ppm. There is also lots of photosynthesis occurring.

 

[bertoni]

Thanks for the info!

 

[tmz]

You are welcome.

 

[Scubajoe1]

So I have my outdoor air running through the scrubber. typically at night the pH drops to 7.90 by morning but last night it stayed at 7.98 constant. I thought my pH probe was broken. I tested this morning in pH 7 buffer and it read correctly. Finally the pH moved to 7.99 a few minutes ago. I am guessing the action of the scrubber was offset by the usual pH drop overnight. I am sure the CO2 in the water is still reaching an equilibrium as the CO2 depleted air in the skimmer mixes with the tank water. Will be interesting to see what the high pH for the day is. Typically 8.08-8.10

 

[woodnaquanut]

Scuba, what's your pH when you use indoor air? Is that the 7.90 value or 7.90 with outside air?

 

[Scubajoe1]

whether it was outdoor air r indoor air the pH low point was 7.90. My indoor air was not that different than the outdoor air. Now that I put the scrubber on it scrubbing the outdoor air the low point has been 7.98 for two mornings now. High point still only 8.10.

 

[bertoni]

Those numbers all are fine. To raise the pH more, you probably would need to scrub the air over the tank, which could take a lot of media.

 

[Scubajoe1]

Bertoni,
I agree....I was just hoping to get it a little higher. My alkalinity is 7.5 but I don't want to go much higher with biopellets from everything I read.

 

[bertoni]

The tank might be fine with a higher dKH level, but that's not guaranteed. Raising the alkalinity will have only a tiny effect on pH, though.

 

[Scubajoe1]

So my pH started going down some today and the alkalinity and all are the same. Looks like the scrubber lasts about three weeks at least in the winter conditions of NC. Time to change it out tomorrow morning.

 

[bertoni]

How much media is in the scrubber?

 

[Scubajoe1]

It's about 2 cups. It was not depleted. It's still going as usual. Was a slight drop for a couple days then back to normal. Must have been because I closed all my windows. Got kinda cold here.

 

[bertoni]

Okay, thanks for the info.