Exclusive Bashsea design allows for 75% of the filters volume to adapt to water level changes due to evaporation, unlike the industry standard of 10 to 20 percent. This minimizes the possibility of pump failure due to running dry and greatly reduces the frequency of water level maintenance. True Union Drain Assembly for fast and easy installation and removal. Constant Water Level Skimmer Chamber. Large Baffle Chamber located before pump to minimize bubbles. Pump chamber allows for internal or external pump.