An acceptable cyst product should contain minimal quantities of impurities (e.g., sand, cracked shells, plumes, salt crystals, etc.). Hatching synchrony must be high: when incubated in 35 ppt seawater at 25^°C, the first nauplii should appear after 13 to 16 h of incubation and the last nauplii should have hatched within less than 8 h thereafter. This is important because the practical aquaculturist normally wishes to harvest the nauplii and feed them to the cultured shrimp as soon as possible. When hatching synchrony is low, first-hatched nauplii will have consumed much of their energy reserves by the time the last nauplii have hatched. Hatching efficiency (the number of nauplii hatched per gram of cysts) and hatching percentage (the total percentage of the cysts that actually hatch) vary substantially among different batches and obviously account for much of the price differences. Hatching may be as low as 100,000, while premium quality cysts from Great Salt Lake yield over 250,000 nauplii per gram of cysts and Brazilian or Vietnamese cyst batches may have an even higher yield, i.e., over 300,000. The possible biological mechanisms responsible for these differences have been reviewed (Dhont et al.,1993).