1st alk prob in 9 months/ need help

[Orion80]

So i have been able to get my ca up to the 450 range, and my alk has dropped to about 12 dkh, and I have sarted to drip kalk again, so that should b stable. But my ph is still low midddle of the night it is sitting at 7.74 and during the day tops out at about 7.95. Is their a way now to bring up just my ph without bring up my alk??

would staight vinager wrk to do this. So far all the buffers I have bring up both my ph and alk, but the ph drops back down to what it was soon after. I have recalibrated my ph monitor 3 times, still get the same readings could it b that the probe is shot??

Adie