errant pH readings ?

[gregzz4]

Originally Posted by Wheelman76

I'm dealing with the same thing right now. My tank is four and a half months old and my ph has always hovered between 8.15 and 8.25 during lights on and it drops down to 8.05 to 8.10 at night and I run the light in my refugium 24/7. For the last three or four days the ph won't get above 8.12 during the day and drops to 7.97 at night. I know it's not a huge difference but it's bugging me. It must be the weather since we are both dealing with this problem at the same time. I have my balcony door open all day and night as I have for the last few months and have made no other changes, so I think it must be excess co2 causing the drop in ph. Btw my alkalinity sits between 8.4 and 9.0 and I have an apex controller that reads the ph , which I just calibrated three days ago when I noticed the drop. I plan on running a tube from the air intake on my skimmer out my window to see if it makes any difference.

I'm looking forward to your observations once you find something different to explain what is happening to your tank

I can't change what I'm doing as I have the doors and windows open as much as I can