Hello, thank you for the review, all feedback is important to us. We are sorry to hear about your experience. The pump you purchased is intended for fountains not for ponds, especially with Koi in them. If you would like help finding the correct pump, please contact our Customer Care Team at 1-888-412-6001, Monday –Friday, between 8:30 AM to 5 PM ET. Your TotalPond Water Gardening Specialist, Cindy