Cajun,I use a 4 inch trash pump on large jobs, we get about 1 ft of drop (or fill)in 13-14 hours at 400 GPM,(1/2-3/4 throttle) the downside these pumps weigh 150 -200 lbs,get one on wheels. Renting is the way to go as a good pump with a Honda 11-13 hp will run you $2500-$2700,rent $50 per day. The oil alert feature is a great item as engine shuts down with low oil and may save an engine.You will find when the pond is almost empty that you need to run at 25% throttle as the very bottom water cant get to the suction area fast enough to keep the pump primed.Good Luck, PS Keep those hands and arms out of the way of the suction line as a 4 inch pump can snap a limb (real fast)
