Personally, I'd say skip the pre-filter (almost considered it myself) and go 100% polyester fill(aka pillowstuffing) in the bottom tray (really good at polishing your water) and biomax rings in the remaining trays. The poly-fill I bought was from an arts and craft store (skip the fluval polishing pads) and I've had my bag since April and it'll probably last me well into this upcoming summer .. and that's replacing at least 1 tray's worth every 2 weeks ... Paid $5.00 for it. Just ensure it doesn't have any fire retardants, perfumes etc.
While a 205 is rated for up to a 40gal max, if possible I would recommend going up to the 305 ... always a bit better to have a filter rated higher than your tank's volume. If you can't go with a 305, then maybe do a second filter like an HOB
that can handle up to 40gal.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.