Just lost week old brine shrimp. Why?

[vessxpress1]

Hey guys, I just hatched out my first round of live brine shrimp. Actually hatched way too many. Was growing them out in a gallon bowl. The bowl got kind of cloudy so I tried to siphon out the liveliest ones and changed out half the water with new saltwater last night. This afternoon, they're almost all dead. Only a few remain a live. I thought these things were tough? Could a pH or temp swing wipe them out this easily? I had way too many in the bowl with cloudy water so they weren't going to make it leaving it alone. I was trying to reduce numbers and make them last. Been feeding spirulina powder and have had a bubbler in it. No heater. Just leaving it at room temp, 68 degrees. Massive loss over the day today. Does it need light on 24/7 or can light be turned off at night? I've been turning it off. Hope to not screw up the next batch.

 

[Cory]

Maybe take a pic or video of your brine setup.

 

[vessxpress1]

Well, it's basically a 1 gal fish bowl with an air line in it. I added a tiny bit of spirulina each day or every other day. have it marked for evap tracking but keep the top covered. The water is 68 degrees. I think I may have mixed the salt a little strong in the replacement water. 1.030. Supposedly they can live in that. Maybe it was a pH swing.