[PvtPublic (Peter)]

I am new to astronomy and have purchased an LT6. After probably a dozen or so nights of observation Im having trouble getting the slew speed to change and most recently had trouble with the mode button not returning me to the previous menu. For some unexplained reason I was under the impressiion that in order to change slew speed I needed to press "5" on the controller then any number between 1-9 for the corresponding slew speed ( I have been changing the slew speed in this manner since purchasing the scope ). After consulting the manual I could not find anywhere that said the "5" had to be pressed before choosing a slew speed so I began skipping the "5" button press and was able to change the slew speed until my last observing session where I could not change the slew speed again. Pressing "8" then a number between 1-9 enabled me to change the slew speed again. Does anyone have any experience with this hand controller and these types of issues?
Also would I benefit from an OIII filter with a 150mm aperture?