delete channels

#1
hi, i have discover with the last versions of the program that
for me is impossible to delete channels.
because i have 8 tuners and each tuner save 300 channels,
is like i have 2.400 channels stored and maybe for this
the program make to run only 5 of 8 tuners.
i have try to delete some mux from 1 tuner, but after
when i search a channel on the list, they appear again.
how is possible to delete some mux from 1 tuner ???
thank.