No, my problem wasn't that I wasn't decapping. And as I said, my babies are surviving and growing nicely now.
My problem started out that I listened to the wrong advice. Someone that sells them told me that 2 dwarfs would not potty enough to even worry about cycling the tank. So my first dwarfs came and had a HUGE batch of babies the very first week and my tank wasn't ready. Bit by bit they all died.
My 2nd batch came and the people (a different company) did not send them in styrofoam and they sent them over the weekend so they sat in the bag and got so hot. When I got them straight from the mail man, they were in bad shape. One was missing one eye. 2 were obviously dying. The ones that were left were too stressed. They all died in the first couple of weeks.
I had one survive and just had her for awhile. The tank finally seemed stable so I added more. Since then I only had the one death of an adult and that was the daddy that came in that last shipment. Now the babies are all doing wonderfully.
As for decapping, I don't think it's needed. I have no problem separating the brine. BUT, I don't think the brine is the very best food. I'm working hard to get them trained to a plankton that has various types of frozen foods in it and they are eating copepods which I culture. I'm cutting back on the brine. I don't feed them the baby brine too much anymore. I feed them the 2-4 day old enriched ones. I find that if I feed the brine at the same time as the frozen a few will try the frozen. I've talked with others that have gotten their dwarfs onto a frozen diet. Hopefully, I'll do it too. But the copepods are the best thing I think. The brine is more for delivering medicine and vitamins.
Suzi