Daphnia

So I bought a bunch of Dapnia from Dallas Discus. I also found some locally, but very small.
I put the daphnia in old fish water- with no nitrites, etc...
I feed them fine ground fish food, and greenwater. I went from about 1,000 in a 5gal bucket to about 100. I have not been feeding them to my fish yet as I hoped to build a larger colony first.
I did take some out and add to various jars and a kiddie swimming pool which I have not checked on yet as it is burried in the ground in the middle of what has become a giant burdocks patch.
What do I need to change to make these guys successful?
I keep the bucket outside on my north facing porch. They get some morning and evening sun, but no major heating sun.

I'd recommend using the kiddie pool to culture daphnia. Larger containers are best.

Get some ducks. They are great for daphnia.

We culture daphnia in our lab for fish food. You'd be amazed how many you can get in a single 10 gallon tank. We have some goldfish in a 20 long that make lots of green water. We try and keep the daphnia culture green or at least not clear. Do that and they will boom. Whatever you try and culture them in, you must try and keep it green. We do 50% water changes 2-3 times a week with new green water.

Cheers
Peter