First of all let me say I hate the look of dye in my lake. Sadly there is no choice unless we are willing to let weeds take over. Dye is theoretically the safest and easiest way to stop weeds.
So how blue? How much is enough? I put a football sized white in the lake so the very top of the rock is 18" below the surface. My plan is that as long as I can not see the rock the lake is blue enough to stop the weeds but I totally just made that up. Does anyone have a more scientific suggestion?
FYI be careful on the south side of my dock. There is a big white rock there : )