Normally I don't manage to get enough green water to make the tub viable
You do not necessarily need green water, dried leaf litter and clear water do as good a job to feed Daphnia. My tub stands in the garden relatively shaded under a Hedera ivy and next to a Passiflora this drops dried leaves in the tub also the neighbours Chestnut tree helps. The only thing i do is take some leaves out if i feel its too much. It's never green water always clear.
As said always Daphnia.
As a kid, i used to go and catch them in the farmers' meadow. The big cattle drinking throughs are always littered with Dhapnia and the water is always crystal clear.
I guess the Green water Urban Myth is something developed from keeping daphnia in a small volume.. Then it's pretty normal that it booms and busts with the idea it's caused because the water is no longer green. But that isn't the case, in larger volumes also in clear water, i also notice booms and busts, But a 95% bust with the population at 200.000 is enough numbers and survival rate to still feed your fish once every few days and make a boom again.
What the exact cause is for the bust or 100% mortality i have no clue and only speculations. Since they are so darn sensitive it could be tiny swings in environmental parameters.
Could be they boom each other to death with their own poop?
