Waymon :

I am leaning toward a combination program on the pond in question using small amount of fert. and feeders . I hope the combo will offset the reduction in fert. Like you we do not have a weed problem.

I am not sure that I understand your water level control system. When your pond is full {but not losing water} and it rains and water level starts to rise does the water that flows out of your system come from the top 3 feet of the water column or from 7 feet? Our system takes the water from 5 feet and sends it through a 8 in. pipe into the standpipe and out behind the dam. We loose almost no water{except in winter} over the top of the standpipe which is 3 feet higher than the 8in pipe. If you can stop the loss of the top 3 feet of water then fert. will be much easier and less expensive.Good luck and let us know what happens. ewest