Surge Tank and Pre-Filter
 

I plan on running a surge tank in my FC but want to keep it as simple as possible. I'll be running an older RP intank pump, a Bosch 044 external and I'm already using the Marren fine element (150micron) filter mounted inplace of the stock filter. The intank pump has the factory "sock" on it. How important, or is it even needed, to have a 10 micron or equivalent filter after the surge tank but before the Bosch Filter. The sock was good enough for mazda to filter fuel before the pump, why not in this situation? Fuel will pass through the sock before it goes to the surge tank and the 044 pump. Then the main 150 micron filter before the injectors, before it goes back to the surge tank. To me a 10 micron filter after the sock seems redundant, yet I always see it so there must be a good reason for it.
Any help or advice is appreciated.

-B