Reducing CO2 pH drop during party

[re76]

So for Halloween my girlfriend and I threw a big party, with around 10-12 people and a lot of beer and drinking. It was a great party, but that night I noticed on my Apex that my pH took a HUGE drop from about 7.96 to 7.20. All of the activity took place in the dining room, which also happens to be where my tank is. My hypothesis is with that many bodies, and all of the carbonated beverages the CO2 in the air made my pH plunge.

Luckily over the night it bounced back to 7.9 and nothing died. At the time I only had 2 peppermint shrimp and some blue-leg hermit crabs in the tank. I now have two clownfish as well.

My girlfriend is talking about having another big gathering of the same nature, lots of people and lots of beer, for New Years eve. I am trying to figure out what I can do to safeguard my tank so that this doesn't happen again. BTW I have a rimless 90 gallon tank, a Red Sea Reefer 450.

Basically some of my ideas are:

• Run skimmer air line temporarily out a window to get fresh air
  • I think this would help but I don't know if it has the kind of turnover to fight the large amounts of CO2 in the air.
• Run an air stone into my return pump that it pulling air from outside to pump micro-bubbles into the tank, and hopefully drive out the CO2
  • I think this might be my best bet. I would have to explain why my tank is cloudy, but I could care less. I could always just start the bubbling once the drinking starts and people have had a chance to gawk at the tank.
• Put saran wrap over the top of the tank
  • I'm thinking this in conjunction with the micro-bubbling could create a positive pressure environment inside the tank to help keep high-CO2 air out while oxygenating the water with outside air at the same time.

Am I overthinking this? Has anyone else noticed similar issues when they have a bunch of people in the same room as the tank?

Thanks in advance!

 

[Marquiseo]

Another (cost) option would be to buy a tank of medical grade oxygen and put an airstone on the end and let it oxygenate the tank. You would have to dial it in slow to make sure it doesn't raise the pH too high.

 

[cowboy]

You should be fine by simply allowing your skimmer to draw air from outside. The skimmer injects a large volume of oxygen into the tank more so the the top of the tank and going through the sump. I personally would bother with the other 2 options.

 

[n2585722]

I have the same issue when the 5 grandkids spend the night. The pH drops. I also have the skimmer drawing air from outside the house. I have had no ill effects with this happening though.

 

[re76]

Another (cost) option would be to buy a tank of medical grade oxygen and put an airstone on the end and let it oxygenate the tank. You would have to dial it in slow to make sure it doesn't raise the pH too high.

Ohhh I never though of this. This is intriguing, do you have any idea how much this costs by any chance?

 

[nervousmonkey]

+1 to Cowboy
You could also buy an air canister from BRS and soda lime, then run your airline to your skimmer through the canister with CO2 scrubbing soda lime, so before the CO2 can get in your tank, it is already being scrubbed out. This will help your pH on a permanent basis as well. You'll easily see a 0.2-0.3 increase in pH. Another idea would be to add some kalkwasser top off water to the tank during the party. The kalkwasser scrubs CO2 out of the system very quickly, so you won't have any dissolved CO2 in the DT and no pH drop. Be careful with the kalk idea though, as not to put too much in. You could add the pre-prepared kalk to the DT about halfway through the party and you'll see the pH won't drop, or will increase back to where it was. If you want a place to buy cheap soda lime, PM me, or PM me with other ideas that will help.
And @cowboy is correct, putting saran wrap over the tank is taking care of about 1/1000th of the CO2 entering the tank. Most of the CO2 is coming from your skimmer, so if you want simple and easy, run the airline outside and you should not see any pH changes.

 

[Marquiseo]

Ohhh I never though of this. This is intriguing, do you have any idea how much this costs by any chance?

I don't have a rough estimate. You can check with your local Air and Gas company for the best pricing.

 

[re76]

+1 to Cowboy
You could also buy an air canister from BRS and soda lime, then run your airline to your skimmer through the canister with CO2 scrubbing soda lime, so before the CO2 can get in your tank, it is already being scrubbed out. This will help your pH on a permanent basis as well. You'll easily see a 0.2-0.3 increase in pH. Another idea would be to add some kalkwasser top off water to the tank during the party. The kalkwasser scrubs CO2 out of the system very quickly, so you won't have any dissolved CO2 in the DT and no pH drop. Be careful with the kalk idea though, as not to put too much in. You could add the pre-prepared kalk to the DT about halfway through the party and you'll see the pH won't drop, or will increase back to where it was. If you want a place to buy cheap soda lime, PM me, or PM me with other ideas that will help.
And @cowboy is correct, putting saran wrap over the tank is taking care of about 1/1000th of the CO2 entering the tank. Most of the CO2 is coming from your skimmer, so if you want simple and easy, run the airline outside and you should not see any pH changes.

Ok. It sounds like I am underestimating the amount of gas exchange that happens in the skimmer. It just doesn't seem like the GPH of water that cycles through the skimmer is the same as what is exposed on the surface of the tank when the surface is being agitated by a power head.

I do like the kalkwasser idea though. I have some on hand already, but have not had to use it yet since I have no corals in the tank. I think maybe I will just go with the skimmer line through the window and have the kalkwasser ready in case I see the pH dropping.

 

[nervousmonkey]

I like the idea of adding O2 to the water column, but oxygen is a super powerful oxidizer (bit of the obvious there), and too much is dangerous for tank inhabitants. It's akin to letting ozone into your DT. The problem is too much CO2, not lack of O2, so I would go the route of keeping CO2 out of the tank in the first place.

 

[Marquiseo]

Also, I don't think any other solution besides opening doors and windows, using soda lime, or using the medical grade oxygen with an air stone. As the home fills with guests, CO2 levels will rise in the home. Your skimmer will still input CO2 into the tank along with oxygen; the skimmer won't discriminate. Also, if you cover your tank with saran wrap, it won't effectively exchange gas because it will be enclosed at the main body of water where most of your gas exchange is occuring.

More CO2 = Lower pH
More Oxygen = Higher pH

 

[re76]

Also, I don't think any other solution besides opening doors and windows, using soda lime, or using the medical grade oxygen with an air stone. As the home fills with guests, CO2 levels will rise in the home. Your skimmer will still input CO2 into the tank along with air; the skimmer won't discriminate. Also, if you cover your tank with saran wrap, it won't effectively exchange gas because it will be enclosed at the main body of water where most of your gas exchange is occuring.

Well what I am considering is running the air intake of the skimmer out a window for the duration of the party so that is it pulling air from outside, where we can hope there is far less CO2 in the air than there is inside.

Normally I would just open the windows, but January in Pittsburgh is not great window-opening weather.

 

[Marquiseo]

Well what I am considering is running the air intake of the skimmer out a window for the duration of the party so that is it pulling air from outside, where we can hope there is far less CO2 in the air than there is inside.

That should work. I didn't read the portion about running the line outside from the original post. Good luck and have fun at your party.

 

[nervousmonkey]

Ok. It sounds like I am underestimating the amount of gas exchange that happens in the skimmer. It just doesn't seem like the GPH of water that cycles through the skimmer is the same as what is exposed on the surface of the tank when the surface is being agitated by a power head.

I do like the kalkwasser idea though. I have some on hand already, but have not had to use it yet since I have no corals in the tank. I think maybe I will just go with the skimmer line through the window and have the kalkwasser ready in case I see the pH dropping.

You are correct, the skimmer is responsible for most of the dissolved air in your tank. The tank surface is actually covered with a film that most can't see (and why surface skimming is so important), which limits the gas exchange at the tank surface. If you think of the square area of your tank surface, then compare that with with the square area of the skimmer bubbles, you'd see what I'm saying. The numbers are not even close. Let your skimmer do the work; it's not the GPH of water through the skimmer, it's the contact time with air and water from the bubbles. Area to volume ratios in chemistry show this as well.
I like your idea, the skimmer line through the window will be enough. If the pH still drops, just add some kalk water to your skimmer intake area and it'll kill the CO2 quickly.

 

[beaslbob]

imho you're overthinking it.

 

[re76]

imho you're overthinking it.

This is my tendency with all things, and why I like to talk about these things with people who are smarter than me.

 

[mcarroll]

Well what I am considering is running the air intake of the skimmer out a window for the duration of the party so that is it pulling air from outside, where we can hope there is far less CO2 in the air than there is inside.

Normally I would just open the windows, but January in Pittsburgh is not great window-opening weather.

Open one window, somewhat near the tank if possible, and run a fan in the room – maybe pointed from the window at the tank.

And just open the window enough that the temperature in the house doesn't drop.

Enough bodies to raise CO2 levels would also raise temperature. So that's a fact on your side.

 

[Breadman03]

Ohhh I never though of this. This is intriguing, do you have any idea how much this costs by any chance?

Look at risk vs. benefit here. Do you really want the risk of pure oxygen in your house, setup to DIY standards?

http://www.space.com/17338-apollo-1.html

Given the short-term nature of your problem, I would run an oversized airline outside for your skimmer and consider leaving a window open near the tank.

 

[re76]

Look at risk vs. benefit here. Do you really want the risk of pure oxygen in your house, setup to DIY standards?

http://www.space.com/17338-apollo-1.html

Given the short-term nature of your problem, I would run an oversized airline outside for your skimmer and consider leaving a window open near the tank.

I actually totally understand the dangers of working with pure oxygen. In undergrad I worked in a research lab that dealt with all sorts of ultra pure gas doing semiconductor research.

I figured medical grade oxygen would be some mixture that was more safe. I agree though, that while it is a neat idea, I think there are better and cheaper options.

As far as the oversized airline, how much bigger do you think it needs to be? I would guess the tubing on my Nyos 160 is something around a 1/4" ID. If I used a 1/2" ID vinyl tubing to run to the window would that be enough?

 

[Breadman03]

I'd expect it to be fine, though it's more a factor of how far the run is. I did something similar for a few days and the skimmer seemed to operate the same as before. I was just testing to see if my low pH was due to CO2 in my house or if it was internal to my tank. In my case, I had tank issues that have been getting better and my pH has been steadily climbing as it gets better.

 

[re76]

I'd expect it to be fine, though it's more a factor of how far the run is. I did something similar for a few days and the skimmer seemed to operate the same as before. I was just testing to see if my low pH was due to CO2 in my house or if it was internal to my tank. In my case, I had tank issues that have been getting better and my pH has been steadily climbing as it gets better.

Ok. My tank is pretty close to a window. It is only about a 7-8ft run. Maybe 9-10 if I try to route it in an unobtrusive way. I think I will just swing by Lowes on the way home and buy 15 ft of flexible 1/2 inch tubing and do a dry-run over the next few days.