I’m glad I found this thread because I’m going through the exact same thing. I went months and months hatching with great success and then all of a sudden boom, hatching rate is great but the BBS die very quickly and fall to the bottom of the hatchery. I have tried all sorts of things, baking soda for ph easy brine shrimp salt instead of fritz salt. Heater, no heater, new eggs, longer and shorter amounts of time hatching and always the same, great hatch rate but they die so fast. I have a second hatchery so I’m going to try what worked for you and let the salinity and heat settle over night and put a batch in tomorrow!
OP if you happen to see this please comment back if you’ve been having continued success with this method of waiting before putting in the eggs! I’m running out of patience and ideas of how to get a good supply of BBS for my apisto fry!
thanks!