Some shrimp hatches failing

I've set up a couple of hatcheries to feed our axolotl larvae (10 days old now) but every so often a hatch will just fail. I think I'm doing everything the same... can temperature fluctuations affect the hatch? Am I putting too much salt in the water? The recipe by Jennifer Macke suggests 1/2 tbsp salt for 1/4 tsp of eggs and 2 cups of water. Now I'm wondering if tbsp means the same here in NZ? I'll check. I'm not using heat lamp and some hatches are great.Any other suggestions? Many thanks.

The only thing I can think of is to check the pH of the water. Your tap water may vary, and BBS need water that is on the alkaline side. Also, what do you do about the chlorine in the water (and do you have chlorine or chloramine)?

I haven't been doing anything about the chlorine in the water. I've been using tap water to hatch the BBS and maybe I should be using the 'tank' water we get from the pet shop? What do you mean by 'do you have chlorine or chloramine'? Do some water supplies have chloramine added? I don't know what this is sorry - pretty sure we are chlorinated. Have checked tbsp conversion and it is not significantly different so I don't think that is the problem.

I'll let you know how it all goes with the 2 hatches bubbling away at present. I have printed out your info on 'Microfoods for larvae' and it's terrific. We have a couple of microworm cultures going also - I get the impression the axies don't eat as much of the worms as the BBS (don't like them as much?) and they don't generate the same reassuring orange glow in the belly!

Thanks so much for your prompt help Jennifer.

It does matter whether you have chlorine versus chloramine, and I can think of 3 ways you can find out which one you have: ask a local petshop, call your local waterworks, or do an ammonia test on your tap water. If fresh tap water tests positive for ammonia, you have chloramine.

Doing nothing (for water to hatch BBS) is OK if you have chlorine - the chlorine will dissipate before the BBS start to hatch. If you have chloramine, then it needs to be put through a drinking water filter, or use bottled water. Don't use chemical dechlor products, as BBS can be sensitive to them.