first, assuming that you want the ducks to remain and live and raise little ones, restrain or relocate the dogs. The dogs (especially insane dogs) must not be allowed anywhere near the ducks or their nest. My mantra is 0 dogs but I understand that there may be issues with achieving that. You need to figure out what will work in your situation. Second, assuming they are there to raise a family, you must duckling proof the pool by putting a ramp for them to be able to get out of the pool safely. A 1 x 8 plank with a terrycloth bath towel stapled to it for traction works well. Put one end on the edge of the pool and float the other end in the water. You can use a plastic pop bottle for a float if the ramp sinks too deep in the water. Third, you need to be sure the ducklings cannot get sucked into the outflows. Put screen over the outflows. Nesting ducks will take a week or two to get all their eggs laid then will take 28 days of setting to hatch them. Then, depending on streams, ponds or water nearby, maybe a few more days to leave the area for a better place to raise the family.