While I applaud your setup including staged filtration of 10 micron then 2 micron, in my opinion you are over-filtering your fuel.
First, your biggest issue is water. Solve that and your other issues will be manageable at any filtration - algea forms at the boundary layer of fuel and water. Remove the water, and you remove the host conditions . You do not mention what type of racor filters you have, but you must move enough volume of fuel to move the moisture along with it.
Second, assuming you do have some sort of biological matter, on a molecular scale, it's large particle. You do not need to filter down to 2 micron. 30 micron will be fine for polishing. Your main filtration system will do the rest.
You need to move some fuel here. Tiny pumps do not produce any turbidity in your tanks
which will help dislodge particles.
I can't answer whether hardware
store filters will do the trick. You may want to try a toilet paper bypass filter from. Frantz or similar. But I'd focus on water before you worry about particles.