Racor and secondary filters

[Pieter]

Hello,
I have two Volvo Penta MD2030 Saildrive engines (Catamaran), and i need some guidance regarding the use of the fuel filters.
I use Racor R12T as a pre filter (10 Micron), and my volvo dealer tells me that the Volvo fuel filter (at the engine) is 25 micron... I am confused, why would i have at a pre filter 10 micron and at the engine 25 micron (shouldnt it be the other way around)?
Also, when i purchased my boat, it had a pre filter system, made of a very fine metal mesh screen inside a plastic cup. Easy to clean, and ofcourse reusable. A diesel tec in St Maarten, convinced me to replace those and get Racor. Now, back in Brazil, those Racor cardriges are hard to get (and rather expensive). So, actualy i would like to go back to the fine metal mesh set up, but of course kind find a supplier. In any event, appreciate the input on this matter. Best rgds Pieter Kommerij
SV Lumina
Lumina Charters – Brazilian Coastal Catamaran Sailing