Change Over

Hi All,

I've been a guppy breedre for a couple of years but am thinking about
taking my 30 gal and changing over to african cichlids. How many would I
be able to put. Also how do you tell a male from female and how heavy a
load would it put on my undergravel filter when changeing over. I have a
handfull of adult and adolecent guppies in the tank and don't mind if the
get eaten as feeders.

Dave G.