Hello so I have brought home a second hand aquarium (2 aquariums in two months ... I guess that’s how this hobby goes ) I don’t have anything under my other aquarium. I was wondering, because I just recently seen in shop some rubber mat to place under aquarium, and I also seen someone having a polystyrene under theirs aquarium. What purpose does this serve? And what would you recommend me to do for my new 54 liter long aquarium?