Damned Access Resistance

Hi, I have been patching from several months, I have tried different internal solutions, pipettes with different resistances (ranging from 2 to 7 MOhm), increased the osmolarity of external solution... I have no much troubles obtaining the GigaSeal and going to whole cell, but basically I never get access resistances lower than 30 MOhm after breaking the membrane, often increasing during recording even up to 60 MOhm :(
Do you think that it could be influenced by the PH of external/internal solution? Could something ameliorate if I put EGTA in my pipette?
I'm quite worried 'cause I know that recommended access resistances are max around 20 MOhm, do someone know how my high resistance could affect my data? I'm recording mEPSCs and mIPSCs...
Thanks for any kind of help!!!!