What are some good inexpensive substitutions to regular biocubes and what-not? Like what can I use to filter the water that is inexpensive? Would lava rocks be ok to use?
i tried using an average kitchen sponge once, want to know what happened? the sponge disolved and the next morning there were little bits of sponge-material floating all over the tank and the water turned blue (the color of the sponge i used). a lot of my guppies died that day.