Just wanting advice on tank setups please. I have 2 3ft tanks that have a weir at the side built onto them as there from a fish shop, in the side weir there is brown balls in that must be some kind of media with a white tube with air pump pipe attached to it so can be used as an air pump?? Also what else would you advise to put in my tank (substrate, caves, filter or powerhead, wood etc) for a group of l134s in 1 tank and undecided on the other tank yet but will be either l201, l333 or l183. And would i beable to mix any of these.