Tony:

Koenders has an airline freeze control unit that meters a bit of alcohol into the line when pressure builds. Their instructions specifically say to use 97% isopropyl, their compressors are the diaphram type.

http://www.koenderswatersolutions.com/store/freezecontrolsystem.html

To fill the tank to the recommended "2/3 full" level, it takes 2 1/4 gallons.

www.hoosierpondpros.com

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).