This protocol will make 4 liters. Adjust to your needs if necessary.
Put 3500 ml Milli-Q H2O in a beaker
Weight 17.6 g of MSMO (in the 4°C freezer, 4.4 per liter) and add it to the water (agitating)
Add 30 g/l (120 g for 4 liters) Sucrose
Adjust pH to 5.7 (adding KOH if it’s lower)
Fill with Milli-Q water to exactly 4 liters
Put 7 g of Agar (per bottle) in 4 clean glass bottles and add 1 liter of the mix to each bottle
Autoclave for 35 min
Let cool, add antibiotic to your convenience and pour into plates
Big round plates take about 50 ml of media
Square plates take about 25 ml of media