Diesel return line

[SVCetacea]

I'm installing a dual filter setup on my boat and want to use it for fuel polishing as well.
I going to add a 3-way valve after the filters, one side going to the engine for regular use and the other to be used for the fuel going back to the tank.
Can I add a "T" to the engines fuel return line for the polishing or would I need a separate return line?

The pump is a Walbro FRB-13 that does 43 gallons per hour and I have a 25 gallon tank.

[jrd22]

I'm not exactly sure what you are asking. On our dual racor we have a line to the injection pump from the filters and the return line comes back to a "T" and then two valves so we can direct the return to the appropriate tank. Seems like for polishing you would need to disconnect the line that goes to the inj. pump and route it directly to your return (just bypass going to the engine. We have two fuel tanks so we have two supply lines and two returns. Unless you are going to use a high gpm pump in the system it will take a long time to polish fuel with a normal 12v pump like you use for filling the filters. I thought about doing the same thing, but bought a used, dual racor 1000 set up that I am going to buy a pump for, just for polishing. Someone here on sailnet has a nice setup that I saw a picture of somewhere, hopefully they will chime in here as well.

John