Rainwater is NOT tap, pond or river water.

Rainwater is rain.

We live at 4671 Queensland Australia, and here we have no town tap water at our little house in the bush.
We rely 100% on rainwater for all our gardening, washing, drinking, fish breeding and plankton growing water.
It rains seasonally, water collects on the roof, runs down the gutters, into the tanks, it then gets filtered, goes through the pump, and comes out our taps.

Clean, fresh, unadulterated awesomeness that doesn’t feel gross, smell like a swimming pool, or taste like old mushrooms, dirt and headaches.

Town or tap water.

Town water is initially rain, that falls onto fields, swamps, houses and roads, where it then flows to drains, small creeks, larger rivers then into major catchments and dams. It is then pumped or gravity fed to a treatment facilities where sediment and biological material is removed with baffles and filter screens, and finally chemicals are added to kill the bacteria and algae that has collected in the water.

Fluoride is also added to strengthen the teeth of our children, and/or prevent political dissent and insurrection among the population. Rightly or wrongly, whether you reckon its good or bad for people, none of these things is good for the health of mini water creatures.

That is a major reason why they use things like Daphnia magna for water quality testing. It is the main animal model used for determining water safety, even today. They can not handle things like Chlorides, and for them to survive these must be removed first.

I am told that chemical additives from the pet shop may “age” the water and make it safe for mini-critters. I am also told that simply leaving the water in the sun for 24-48hrs will remove all nasties, and while I believe it is very possible, I personally have no experience with any of that stuff.

If you are using tap water, please accept that you are now doing an experiment.
This is an experiment that I do not recommend, or have any experience with. Because of this your results will no doubt be different to mine. This could be could a good thing, but it could just as easily be a bad thing.

River, dam or pond water.

River, dam or pond water is rainwater to begin with, so that’s good.

But it is also open to the air, plants, fungi and other creatures, which can be both good and bad. That means it has the potential to have species that could infect or eat the creatures, or even just compete with them. These organisms will often be smaller than can be seen easily with the naked eye.

It could contain viral diseases that make can make them sick, prevent reproduction, egg hatching, or just kill them altogether. It could contain plant matter that is toxic to then, or inhibits their growth. Eucalyptus is a great example. It could contain other Cladocera or even just their eggs which will hatch months later. Things like Alona, Allonella, Cyclops etc that then actively compete for resources, stealing their food, and using up their air. It could contain Fungi like Metschnikowia that effect them in a heap of ways, all bad. It could even have a heap of delicious naturally occurring Algae species which they love to eat, and a broad range of micro-nutrients that provide ideal conditions for growth and reproduction, massively outperforming just rainwater alone.

I can’t recommend using anything but rainwater, as every body of water in the world is different, and the risks of failure or contamination are so much higher using anything else.

I do admit it may work awesome, even better than what I do.
It may also fail completely…

I do sell 25micron filter socks that have the ability of filtering out most fungal spores, algae cells, and Cladocera species eggs, and this may increase the success rate of your experiments if you are using wild sources of water.

Reverse Osmosis(RO), Distilled, Bottled(Spring, Filtered, Glacier) or Bore.

All are water, but all are chemically quite different to what is found naturally in creeks, ponds and dams.
They will all be free of most parasites and competitors, which is good.
The reason why there is no life, is bad though, as it means conditions are not suited to the formation of life in general.

They don’t contain enough minerals, or the minerals they do contain are not in the right balance.
Some additives like Chlorides stop algae formation on supermarket shelves, but are also toxic to the algae the mini-critters want to eat, or even the critters themselves.
In the case of some mineral and bore water they may even contain toxic amounts of salts, sulfur or metals.

For these and many other reasons I don’t recommend them at all.

I can’t offer any advice on their use, as I have literally never used them.
They may work fine, but they may also be a total failure.

If you do decide to go ahead with them, please accept that you are now doing an experiment.
This is an experiment that I do not recommend, or have any experience with. Because of this your results will no doubt be different to mine.
This could be could a good thing, but it could just as easily be a bad thing.

These sources of water may in rare cases cause great success, or much more likely, complete failure…

Guarantee of success.

Long story short, using rainwater and following my instructions, I personally guarantee success hatching my eggs, and initial survival of live cultures.

Using anything but rainwater, and you are doing an experiment. I have no control over that experiment, or the results you may get.

I would really love to hear about if you figure out something cool, or if you have a really high success rate doing something unusual!

 

TLDR

Rainwater good, everything else a gamble.
I guarantee successful hatching and initial culture survival with rainwater, but not with anything else, as it isn’t something I have ever done.