All geo strains differ in their properties (yeast/mold appearance, wrinkling intensity, color, aroma, etc). Use 1-2 doses per 1000 liters, use whatever you have on hand, or start with geo 15 if you need to order. For a small scale, this means, a tiny pinch if using lyophilized powder, or a few drops if using the hypotonic liquid. It will grow very quickly. Aging temp is important... chill it down to mid 40s as soon as you have a good coating.