Calculate settings for automatic 2 part dosing:

#1) TOTAL VOL. OF CONTAINER / # OF DAYS = DOSE AMOUNT SETTING LM3

#2) NO. OF DAYS * DAILY REQUIREMENT  = AMOUNT 2 PART IN CONTAINER

#3) ADD RESULT FROM #2 to container and fill the rest with RO/DI.

Detailed info here: http://stonyreef.com/blog/2009/automating-two-part-dosing-with-a-litermeter-3/

Spectrapure Litermeter 3 Peristalic Dosing Pump - Great for automatic dosing of two-part solution and top-off of your reef aquarium with RO/DI water