Tapwater for daphnia

[gcalberto]

I have kept daphnia for a while, for one reason or another I sometimes would rather not use aged aquarium water for them. Does anyone know if tapwater with some water conditioner can be used for this purpose? 

[Daniel]

According to this document issued by the Environmental Technology Centre (government of Canada), dechlorinated municipal tap water is acceptable for culturing Daphnia

[Cory]

From my testing over the years, there is a chemical in a lot of the common dechlorinators that kills the daphnia. This is why "aged" water is recommended. I don't know which specific chemical it is. It would be worth someone figuring that out I suppose as new clean water would be much easier with the right dechlorinator. 

[gcalberto]

Both points seem to be very interesting. I'll try putting some daphnia in with tapwater and my tetra declorinator and see what happens 

[pedrofisk]

I think some species are more hardy and can put up with de-chlorinated water better. Unfortunately you can never really know which species you're getting.

[gcalberto]

I got mine as daphnia magna. Not sure if it helps 

[Daniel]

The document mentions D. magna and D. pulex. Other than assuming you have a lab, their section on raising Daphnia is okay.

[Meow Aquatics]

I've read about people using vitamin c to dechlorinate. Supposedly works on chlorine and chloramines. Also better for the fish. I have well water so I've never looked in to it to see if its a thing or worth doing. I'm sure people above my pay grade can clarify it. 

[pedrofisk]

17 hours ago, Daniel said:

The document mentions D. magna and D. pulex. Other than assuming you have a lab, their section on raising Daphnia is okay.

Do you have a link for that article?

Over on the Live Food Cultures for Aquariums group on FB a member posted this article on Dapbnia form a mareine biologist/hobbyist: http://wako.aka.org/~WebContent/Articles/DaphniaCultureMadeSimple.htm?fbclid=IwAR1NluY3e5wC1ggcKaQ2l2JO2nsvqW6d5U4NYa73Y30AaxKeaMYj4fljClA

Here is an interesting paragraph on water conditions for Dapnia. Especially the part on phytoplankton and phosphorus.

"Literature searching on water parameters that daphnia are sensitive to you find that they are fairly tolerant of ammonia, intolerant of nitrites, somewhat tolerant of nitrates, and have an interesting relationship with phosphorus.  It turns out that daphnia use phosphorus as an environmental cue to reproduce or not.  In nature, daphnia reproduce most rapidly when algae (phytoplankton) are rapidly growing since micro-algae (phytoplankton) are the usual food for daphnia in lakes and ponds.  When algae is rapidly growing and is at a high density, phosphorus in the water is usually low, because the algae are rapidly using this up as a food source.  So daphnia reproduction is linked to phosphorus levels.  High phosphorus indicates to the daphnia’s physiology there is no food (i.e. algae) in the water and cease reproduction.  Low phosphorus level indicates to the daphnia’s physiology there should be high algae levels so kick reproduction into high gear.  This is one of the reasons water changes are very critical to daphnia culture success! "

[Daniel]

16 minutes ago, pedrofisk said:

Do you have a link for that article?

Biological Test Method: Acute Lethality Test Using Daphnia spp.