Here is what I see:
Heating 80 gallons via electric is going to get spendy
Gravity flow in top, "pump" out bottom? The bottom is where the water and sediment is.....Not to mention the cold oil will settle to the bottom. The warm oil is on TOP. Thats exactly what you dont want to put in the CF if it can be avoided.....COLD, heavily sedimented, WET oil.
"Pump" out bottom? Are you going to use a gravity feed CF, or pressure driven unit ala Diesel craft? Perhaps a peristalic pump and gravity???
Here is what I can recomend after running a little bit of oil in my day......
Use as small of a WH as you can find fed by gravity from an elevated vessel. The small WH acts as a mini appleseed processor. Trace amounts of water does appear in my 5 gal WH, virtually no free water visible in CF rotor.
The WH you have can be an awesome appleseed. Heat/settle in the 80 gal. Pump from bottom after draining water and sediment to an elevated vessel. Build up a "pipe bomb" type heater to be put inline before CF OR find a small 5-10 gallon water heater and use that after the appleseed and before the CF.
A good long hot settle and a 140 degree trip at about 8 gph thru the CF and you will have NO problems with fuel quality...........
Let me know if I can be further help
99 F350 7.3
320K w/ 150k+ on Biofuels
Casserly Stage 2's-TE Modded 17 HPOP
DP Tuner F6 & PMT1-Van Turbo Non EBPV & 6637
Twin Fass Pumps B100 & D2 Regulated Return- Fuel Lab
Isspro Pyro, Trans, Boost-Air and Fuel Temp
WVO processed by Simple Centrifuge
B100 by Biopro 190
B100 powered Excursion, F250 CCSB, and Two TDI Jettas