I have a Kent Marine Nautilus EX 24 skimmer. The footprint is 8X8 and is rated for 575 gallons by the mfg. It came with my 300 gallon tank which I bought used. I already had a skimmer and this one has been sitting unused for a while. The skimmer has been modified to increase airflow and has no cracks or damage of any kind. I would like $100.