I'm putting in a small (approx. 56"x56"x3', approx. <500 gal.) pond. At present, the plan is for dry stack, surface bonded cement (quikwall) walls, lined with EPDM, and capped with limestone blocks. The pond is intended to house comets, mosquito fish, and (maybe!) 1 koi, along with some plants.

Water will be recirculated through an old firehose nozzle (1.5") placed above an adjacent retaining wall and pouring into the pond. Plumbing to the nozzle will be 1.5" flex PVC, running 25' to a pressurized filter (tentatively TetraPond 2500), and thence to a Sequence 750 external pump. I plan on fitting the pump with a filter basket. The pump will be installed approx. 10 feet from the pond and on a level approx. midway between the surface and bottom of the pond. I'm shooting for around 1000gph.

What I'm trying to figure is how I should plumb the intake for the pump. I've considered a bottom drain, but two questions are holding me back, 1) I simply don't have room for a settling tank of any size, so I'd have to plumb the bottom drain directly to the filter basket/pump combo and I've read dire warnings about emulsifying debris/waste, and 2) is the 2" intake on a Sequence Pump a limiting factor (i.e., would taking a 3" pipe down to 2" create problems like clogging?), and 3) with a small fish load, is a bottom drain really neccessary? I'd appreciate any advice from more experienced ponders. Thanks!