Surface tension will degass the water a little faster. I had my lily pipe half in and half out once and it changed the ph by something like 0.3 compared to normal. It wont cause a hard ceiling though.
I'm a little confused by the way you are wording your post though. Have you tuned your co2 via a bubble counter or not? That's the first step. Increase it a bit until you lower your ph to your desired target, which can be a little lower than it is now to get to that magical 1 point drop.