I would use either of two filtration schemes, both of which have worked well for me:
1) Dedicated bio-only canister* (Eheim 2211 or 2213) charged with Dupla MiniKaskade balls or Eheim Ehfimech noodles)
only as internal loading, but with a FilterMaxIII prefilter in place of the strainer on the intake. Return spray bar at the bottom rear of the tank, outputs aimed vertically upward.
*Ref:
http://www.thepufferforum.com/articles/ ... ister.html
Mechanical would be by two each Fluval2 (now 2a or 2Plus, not as good but will serve) internals in the corners of the tank, outputs set to provide an overall circular current in the tank.
The canister prefilter and the two internals would be rinsed weekly at least (tap water is fine, bacteria are in the external canister).
Substrate would be aragonite, 2-3mm particle size, ~1/2" depth, vacummed weekly.
2) Biofiltration by OE-RFUG** set with double screens, substrate depth 1-2". RFUG driven by 2 each Penguin 1140s each with Penguin RFUG kit fitted. If the provided prefilter sponge is too coarse, it can be replaced with a FilterMaxI (very fine) or III (moderate).
**Ref:
http://www.thepufferforum.com/articles/ ... lters.html
Mechanical filtration and current as in the first format, filter upkeep the same as well.
Only surface vacuuming in generally needed with this setup, but periodically ornaments should be lifted and their site vacuumed, just in case.
For one F-8 in a 20-long I might drop back to 2 each Penguin 660s to drive the RFUG, but I would likely stay with the larger heavier pump if it did not heat the tank too much. For a 30, it would be the heavier pumps. Ambient temps count here - mine are warmish. I would definitely use the RFUG option for the F-8 because it will provide sinificantly better buffering and alkalinity support in the light BW used for these fish.
For the GSP in the 30, it is purely personal choice, and the canister is less visually intrusive, so more aesthetic. At high BW and full SW, additional buffering is not as significant or as needed. The substrate will stay cleaner and the bioload lighter with the RFUG however.
Both these options are rather equipment-heavy, but that is the way I operate my tanks.
HTH.