Duck pool water is not like chicken poo that needs composted. It's like a high nutrient tea for your plants. Flowers, grass, and veggies will all love it.
I use to obsess over their water, trying to keep it clean. I finally realized its hopeless because all they have to do is take one drink and it's right back dirty again.
Recycling into the gardens is my plan as well but… is there an easier way than baling it out with a bucket? I'm new at this too, and I discovered that about 3 days is the limit -- both for them to enjoy and then I began to pick up a bad smell. They were exstatic when I filled it with fresh water -- but within half an hour, it was no longer sparkling. Oh, well. The garden needs the water, they are so much fun to watch when the water is fresh and they dive and splash around in it, and well, I guess I need the exercise as well. Ducks sure do change one's life!