Where am I screwing up with my setup?
 

On my 93 7.3 dually auto I have a twin tank system. I have 2 electric fuel pumps and a 3 way manual switch on the floor to send the right fuel to the right tanks. I have a centrifuge and I heat my oil to 160 and then run the wvo thru the centrifuge. I prefilter the oil thru socks before it goes into the centrifuge drum. One tank is a 50/50 blend of vwo/diesel. I am in SO FL and the temp does not go to below 45 degrees at any time. If I am going to run the truck in the cold (to me 45 is cold) I will just use diesel. I make a 500 mile trip with the truck over 4days. My oil comes right from the fryer into cubes. I have used this oil for 7 years and I tip the people who control how the oil is transfered. I also have used the same oil in our 300 mercedes with a 20% diesel to 80% wvo for the 7 year period. I have a little over 120,000 miles on wvo so I am comfortable with my oil. I have started up on this blend for 2 years now and have never used straight wvo in the truck. 2 weeks ago as I drove to the store with the truck I got about 1 mile from th3e house and the IP busted. In opening up the pump at the diesel pump repair place they found water and rust in the pump. How do I prevent this from happening again. What type of additive should I be adding to my tank? Should I add a water separator to the diesel side or should both tanks empty into the separator before the injector pump. I only got 10,000 miles on this pump. Any help would be appreciated.:-huh

Your stock tank should be Poly and should never get anything but diesel in it. Is you 2nd tank steel or aluminum? You should only use a SS or aluminum tank with WVO. Is your secondary tank heated? if not, that is another problem. Pulling the thick oil casues extreme wear on the pumps