HI Chuck,
I did some research on the Baby brine shrimp storage and found some interesting facts. In an FAO article they state that fresh hatched Ist instar nauplii can be stored at refrigerator temps with aeration for at least 24 hours and there will only be a loss of 5% energy and minimal mortality. Unfortunately the article doesn't say what effect longer periods of cold storage will have.
https://www.fao.org/3/w3732e/w3732e0o.htm4.3.2. Cold storage
Molting of the Artemia nauplii to the second instar stage may be avoided and their energy metabolism greatly reduced (Fig. 4.3.4.) by storage of the freshly-hatched nauplii at a temperature below 10°C in densities of up to 8 million per liter. Only a slight aeration is needed in order to prevent the nauplii from accumulating at the bottom of the tank where they would suffocate. In this way nauplii can be stored for periods up to more than 24 h without significant mortalities and a reduction of energy of less than 5%. Applying 24-h cold storage using styrofoam insulated tanks and blue ice packs or ice packed in closed plastic bags for cooling, commercial hatcheries are able to economize their Artemia cyst hatching efforts (i.e., reduction of the number of hatchings and harvests daily, fewer tanks, bigger volumes). F
The article did also imply though that at hatching temps the rate of energy use and molting to second stage is very quick occurring in Hours. The first stage is the nutritious one as the baby brine live off their eggs yolks and do not eat .
The main point here is that most hatching instructions say they hatch in 18-36 hours depending on temp.. With a window that big you may miss the actually hatching point, I typically find mine hatch at 20 -24 hours. even so that 4 hour difference is big in terms of nutritional loss. so a few hous makes a big difference.At the high temperatures applied for cyst incubation, the freshly-hatched Artemia nauplii develop into the second larval stage within a matter of hours. It is important to feed first-instar nauplii to the predator rather than starved second-instar meta-nauplii which have already consumed 25 to 30% of their energy reserves within 24 h after hatching (Fig. 4.3.4.).
This is a heavy read..
https://www.fao.org/3/T0700E/T0700E00.htm#TOC
but it gives good information on deficiencies that cause deformities.
hth,
al