[dwalstad]

Recent Question from Hobbyist:

so you don't fear your brine shrimps becoming blue shrimps?
I have still some EDTA lying around...
Do you have an idea, how much I should add for a homebrew water conditioner

EDTA chelates heavy metals on a 1:1 molar basis. To correct metal toxicity, you need to add an equimolar amount of EDTA. For example, my well water contains about 1 ppm zinc. This is 0.015 millimolar (1 mg/l divided by 65, which is the atomic weight of zinc). So I need to add enough EDTA to provide a 0.015 millimolar concentration.

Heavy metals like zinc and copper are not federally regulated and can be present in tapwater at levels that will kill shrimp and totally prevent brineshrimp eggs from hatching. Invertebrates are particulary susceptible to metal toxicity. See my book, pp 9-19.

 

[Juergen]

thank you Diana!
I should have thought of this myself, feeling like a fool right now!
Regards
Jürgen

 

[helenf]

You aren't the only person who didn't think of that at first

I totally couldn't hatch brine shimp, whatever I tried, until I started using a copper-removing filter media to get rid of the copper in my tap water. Now they hatch fine.

 

[dwalstad]

Please....I don't think anyone here needs to feel wanting.

The information on metal toxicity inhibiting brine shrimp hatching seems to be a well-kept secret in the aquarium hobby.

For example, one prominent company selling brine shrimp eggs asked me to test their hatch mix. Well, the eggs didn't hatch in my tapwater (with its 0.8 ppm zinc). The eggs hatched fine if I added EDTA or an aquarium water conditioner or established saltwater (contains lots of natural metal chelators).

I reported my results to the company and suggested that they add a little EDTA to their hatch mix (it only takes a tiny amount and would have been easy to add).

They didn't take my advice.

Brine shrimp eggs will hatch in almost any salt mix or at almost any temperature or at any pH. What will prevent hatching, though, is metal toxicity.

 

[dnrdarryl]

What is EDTA? Where can you get it?

 

[Juergen]

it is a chemical used in water conditioners and other things. Don't know about US, but here small amounts of chemicals are difficult to source and therefore overly expensive.
Probably you are better off buying the 'Tetra Aquasafe' Diana mentioned.
see this thread:
http://www.aquaticplantcentral.com/forumapc/el-natural/showthread.php?t=56795
regards