TrapperUtah,

One thing really spoke to me in your description. Your pond is lined with sand and rocks over the liner. So essentially the soil nutrients are blocked from entering the pond by liner. Given one wouldn't expect sand and rocks to be high in organic matter and nutrients, your observations of dense blooms from the "get go" suggest that the well water is nutrient rich. Have you tested the well water and if so does this confirm this inference?

If your well water is high in nutrients and your pond doesn't overflow significantly, nutrients will rapidly accumulate. You may need to control the nutrients by some other method than dye (for example sequestration by alum/lime). Hopefully esshup will stop by to offer you guidance on what to do and how to do it.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers