I've got a pond in east Texas of 8 acres,2 years old hopefully with some rain it will be 13 acres. I had 20 tons of agricultural lime spread around the banks when it was completed. PH is about 6.9. I plan to build 3 fertilizing platforms and was wondering along with the bags of fertilizer slit open, would bags of lime pellets or powdered lime be helpful. How far below the surface of the water would be ideal for the platform?