The aqurium that i am using for my cichlids is a flat back hex that has oak trim on it. It hold aprox. 49gal. I am not using an undertow filter. The filter sytem that i am using is a Peguin Bio Wheel 330. The bio wheel does everythign that i need it to. It has 40lbs of mixed gravel in the bottom. The rock that i have is mostly sandstone. I bought it at my local pet store. I also have a sponge rock on there. My fish seem to love the sandstone that is placed in the bottom. I have created many different caves for the fish to swim and hide in. The heater that i am using is a submersible one. It has 2 settings for the temps. My temp is usually at about 79 degrees. I also put aquarium salt in the tank. I ahve only 3 plastic plants.