Sponges will indeed attract bacteria regardless. Take it out, a tarantula doesn't need it and shouldn't have it. There shouldn't be crickets running rampant through the enclosure at all times anyhow. There is also not enough substrate height in there for terrestrial species, increasing the risk of falls. Falls which may be injurious or fatal, especially given all of those hard and sharp objects you've placed in the enclosures.I have the sponges for the crickets and they will only attract bacteria if not cleaned properly and frequently.