Wondering if someone could explain the reason for this happening. I have a main pond with goldfish and koi in it. Off to the side I have an area about 5x5 and 2 ft deep that has nothing but plants in it. The same water is being pumped through both. The plants that are in the main pond are looking shabby and yellow, but the plants in the smaller non fish area are lush ,green and growing out of control. Any thoughts on this?