Leaving tank cover open increases PH?

[yeahcheetah]

Noticing my BTA was changing water more frequent than before so I took a measurement of the parameters. Everything else looked fine but the PH is 8.4 (may be higher), higher than usual when I kept the cover closed. Could it because of more CO2 get dissolved in the water? I will do a water change but want to find out where the problem is.

 

[Deanos]

This article should answer all your questions:

Solutions to pH problems

 

[fritz]

Yeah it's not that having an open cover raises PH as much as having a closed cover lowers PH. Allowing the buildup of CO2 causes a drop in PH, by allowing air exchange you prevent CO2 buildup from occurring.

 

[yeahcheetah]

Thanks guys