pH crash, lesson learned

B

bagpiper jim

Premium Member
WOW, Until now I have enjoyed nice pH levels of 8.0 to 8.4 but things got fairly hot here today so the wife closed up the house and turned on the A/C. When I first got home things seemed fine but as the evening went on I noticed that one of my clowns was looking really stressed. I went straight to my aquarium closet and got my test kits and meters out and started testing the water. The only thing I could find was that the pH had dropped to 7.6. I immediately pointed my power heads towards the surface of the tank to get some movement across the top of the water and I opened the house and started the whole house fan to pull fresh air in. I turned off my light hood (only the 2 t5's were on) and within 10 minutes the pH was up to 7.75 and the clown was starting to look much better. It is amazing how quickly things can go south on you. It's also a good feeling to know that with a little quick action you can turn it all around and make things better. Amazing how fast the Co2 can build up when you close the house up for a day. This was a close call but I learned a lot from it.

Jim
 
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I had the exact same problem. It seems to only happen when I run the A/C. During the winter with heating its ok. What I did was run tubing from the air intake of my skimmer to a nearby window. Made a holder out of insulation and sandwhiched with the window. I also put a lock on the window so that it can not open any more than the crack for the tube/insulation. That way I leave it year round and not have to worry about it. Keeps my ph pretty steady.
 
My house is closed up and I use central air. I have no problems, I have never heard of this being an issue.
 
Dont think CO2 buildup is causing this...
Click to expand...

Actually, I think Jim's diagnosis is pretty good. The drop in PH was almost certainly caused by elevated CO2 levels, unless his alkalinity just happened to drop around that same time. Now, would it have killed anything. . .probably not. Could sub-optimal gas exchange at the water surface have been a contributing cause. . .very possibly. CO2 can build up very quickly in a house, though. During the summer when I generally keep the doors and windows closed almost all the time, if I open them up for even half an hour, I'll see a significant rise in my PH. I'm certain I'd see a similar change in my house's CO2 levels if I had a CO2 detector. For that matter, someone on this board was measuring the CO2 levels in his house, and it was almost scarry how high they were.
 
While I understand why Bagpiper did more than one thing at a time (he's not doing a scientific experiment, he's just trying to get the pH down!), there's no way of knowing if just changing the powerheads to agitate the water surface would've been enough.

This is why the hobby has a lot of old wives' tales and myths. No one (myself CERTAINLY included) does things in a scientific way with controls, replicates, etc. I usually change about five things at a time, but I'm trying to stop doing that. :)
 
I hear what you're saying, Biologist, and you're correct. I think the only conclusion we're drawing here is that a buildup of CO2 in the tank from the closed house caused a drop in PH. Given the circumstances and using the already proven concept that such a thing is possible, I'd say the theory in this particular case is at the very least sound.

Since he took more than one corrective action, it's impossible to say if all, some, one or none of them had an effect. But again, the overall conclusion is that reducing the CO2 levels in the tank caused a corresponding increase in PH. Since all of his actions could conceivable accomplish that, I'd say again we have a very sound theory that is more likely than not correct.
 
Why would'nt the powerheads be pointed towards the surface, to agitate the waters surface properly, in the first place?
 
The science experimenst go in the Advanced Topic or Chemistry forum. From what I see Jim you made the right moves.

When you have about 20-30 tanks in the house then you can selectively move powerheads and still have a control of their placement effect on pH. :D
 
All I can say is that I did everything I could do to increase the pH, short of adding buffer to the tank. The only difference from the previous day was that the house was closed up all day with the A/C running. All I could think of was Co2 had to be the cause. All of the other parameters looked fine. I have to say, even I was suprised at the increase in pH after making these changes.

Jim
 
<a href=showthread.php?s=&postid=15257249#post15257249 target=_blank>Originally posted</a> by bagpiper jim
Oops, how did that happen?
Click to expand...

Admin must have fixed it but there was to copies of my last post.
 
<a href=showthread.php?s=&postid=15254404#post15254404 target=_blank>Originally posted</a> by will16
I had the exact same problem. It seems to only happen when I run the A/C. During the winter with heating its ok. What I did was run tubing from the air intake of my skimmer to a nearby window. Made a holder out of insulation and sandwhiched with the window. I also put a lock on the window so that it can not open any more than the crack for the tube/insulation. That way I leave it year round and not have to worry about it. Keeps my ph pretty steady.
Click to expand...
I always thought about doing that but the closest window is at least 20' away... I don't think that i'd get any air coming out of that tube after 20' of sucking
 
This link was my post that IslandCrow was talking about. I run a pump from outside instead of sucking the air in. If I don't run the pump to an airstone, the ph will not climb much at all during the day. IMO air has to be drawn, or pumped into the tank to minimize the prob. if your not dosing kalk. My results are prob. worst than most because I am dealing with a 10 gal. for now.
http://reefcentral.com/forums/showthread.php?s=&threadid=1530009

Lyfey - Mabey your house is larger, and less people and pets breathing in the house than most? Are any of the return air ducts leaking and sucking in fresh air? Not to mention you have a 125 gal. Just a thought. There is no doubt that high levels of co2 will drop your ph. I have watched it, proved it, and tested it. You would not beleive the difference with just my dog sleeping with me instead of sleeping alone. This is an issue with many. Try searching the posts and see what you come up with.
 
This recently happened to a local reefer,
http://reefcentral.com/forums/showthread.php?s=&threadid=1658099
I have been to his place, it is a fairly new (( air tight )) place. Older places won't be as closed up and have less of an issue.

Lucky enough for me, mine isn't as bad when I have the A/C on, since I hate the heat. -- at least not as much of a drop as others have seen. My blue Haddoni does seem to prefer the window being open. When I test the pH it is still around 8, but it is normally around 8.3, been dripping more Kalk which seems to help. The anemone just doesn't open up a wide --- nothing else changes.
 
This is good to know. I've never seen this come up on here before and I never would have guessed CO2 levels could significantly affect pH within a few hours.
 
<a href=showthread.php?s=&postid=15265114#post15265114 target=_blank>Originally posted</a> by dots
I didn't catch where that Alkalinity and Ca test result was? Did I miss it?
Click to expand...

Alk was 3.0 meq/L
and Ca was 395

Jim
 
Yeah, Mike, that was exactly the thread I was thinking about. Thanks for linking it for everyone. I found it rather eye opening. I know my house is a newer one and sealed very well, which is normally a good thing, but even though it's just me (and the fish), it doesn't take long before my PH starts dropping if I haven't been keeping the doors or windows opened. I wanted to do the skimmer pulling in outside air trick, but it just wasn't very practical with where the tank was.
 
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