hadjici
I see you have this question on a few forums around the internet, and from what i have been reading to the replys you have gotten, you have been given some sound advice from some very experienced people, but you come up with new twists to the question each time you are given an answer, basically i dont want to be mean but how many answers do you need!!!
As regards the Ph question iggy has pretty much answered your question, you ran an airstone, if your test kit is giving you different readings go to your LFS and get them to test your water, look in your tank as suggested.....what else is in there, if all that fails do a water change and then test your water, test your tap water as well.
And Tiggs having your co2 shut off at night is not a *must* for you perhaps it is, your tank may be heavily stocked and that may be the reason, i and many others run our DIY co2 24/7 with absolutly no problems to our fish, and if you think about it, its sort of difficult to switch off DIY co2 and i would imagine if you were doing it, it would cause you more problems than it would solve.