I was never a believer in the "closed house keeps pH down"... until now. Check out the pH trend from my system over the last week. The lower limit on pH in my system is typically 8.1 over night. One of my kids had 7 friends over last night and apparently, they breathe a lot! They dropped the pH in my system .25 lower than it normally goes! The pH starts dropping when they arrive and doesn't flatten out until they leave. I would have never believed that our resparate CO2 could make that kind of a difference in our tank pH. I'm plumbing an outdoor fresh air intake to my skimmer!

Dang that is crazy! I would have never thought that would have happened!

It could just be that your tank had an allergic reaction to kids. ;)

How are you planning to filter the incoming air? I'm interested in setting up the same thing for my tank and since it's up against an exterior wall, it should be fairly easy. I was thinking a small inlet into a large PVC chamber with some cotton gauze and carbon that could be changed every 4-6 months.

you can use a large 20oz bottle full of large carbon chuncks to filter out the air. It's only needed at night time really.

Sounds strange, I would not have believed it either but have seen many strange things. I'll be interested to see how your outdoor air system effects your system. I would filter the incomming outside air since in general it may be worse than your inside air (a carbon type air filter, maybe elecrostatic, would probably do the job. Very interesting observation. Keep us posted on the project.

I see it every year. :yes: My wife and kids head out of town to visit relatives for a week every year and I stay behind to work and take care of all the animals. That week my PH stays on the high end (8.3-8.4). As soon as they come home, it starts dropping. The first year they went, I lost a nice sized Orange Linkia star because of the swing. :boo:





D

unfiltered outside air is many times cleaner than inside air. Check out google on home air pollutents. The air inside our homes is DIRTY! I'm not saying dont' run carbon, you don't want the mosqueto fogger coming by and your skimmer injest that lovley chem.

I saw the same thing last week, all of my other params were great but the PH was in the lower range. After exhausting all other options from tons of articles posted here on tank chemistry I decided to leave the windows open in the room the sump, fuge and frank tanks are in and I had an increase of .1 two days in a row overnight that I haven't ever seen before.

I hadn't given the air intake much thought yet. I like the bucket-o carbon idea and will do that at a minimum, thanks for the tip!