I am looking at setting up a rack with 40 gallon breeders, 20 gallon longs, and 10 gallon tanks for breeding pairs, and fry etc. I bought aqua clears (with pre filters) for them all but now am thinking I would be better with one main air pump unit to run corner filters or sponge filters instead so this brings me to my question..... I can't decide on sponge filters or corner filters for them all. What are the pros and cons to using either of these types of filters and what would be best ??? **note sponge filters would run around $14 each and replacement sponge 4 dollars each corner filters are $4 each and I have poret foam I could cut to go in each plus I have lots of bio balls and ceramics on hand as well as lots of filter floss etc. So what way is best????