Our dual tank bulk tank has a single compressor and functions like an old fashioned ice bank. It has a reservoir of chilled water and two separate milk storage tanks. The milk storage tanks can be two 15 gallon tanks for a total of 30 gallons, a 30 gallon tank and 15 gallon one for a total of 45 gallons, or two 30 gallon tanks for a total of 60 gallons.

The Dual Tank approach is:
For those who are milking two species (e.g. cows and goats) and need to store milk from each species separately.
For people who are making butter and ice cream and need to separate the milk into cream and skim and then cool both down.
For small producers who need some flexibility in balancing production. For example, you completely empty and clean your bulk tank every 72 hours and you produce 10 gallons per day. You put 10 gallons in the tank on day 1, you put 10 gallons in the tank on day 2, any milk you put in the tank on day 3 will have to be processed that day, but if you don't need it that day you could put that day's milk in tank 2 and start a new 72 hour clock.
For those who want to pump the chilled water through the pasteurizer water jacket to cool milk down for bottling after pasteurization.

The Dual Tank Bulk Tank includes a 3/4 HP refrigeration compressor, a chiller water circulation pump, a 160 gallon capacity chiller water reservoir, two tanks, two tank lids, two agitators, two indicating thermometers and two recording thermometers. Recording thermometers are required for new bulk tanks installed after the year 2000. The unit is on casters so that it can be moved for cleaning. The price is $8500.

The basic price is $3000 and includes agitator, temperature controller, thermometers and casters to move the tank for cleaning. The chart recorder, if required, is an additional $1000.