30 Gallon Tank Build (Filter)

What are your stocking plans. Who's gonna live there, Oscar or Cory. I think I'd start there and work backwards. I like sponge filters in my breeding tanks along with overflows and sumps, but my corys like to swim down inside the lift tubes and forget how they got in. I use sponges on everything, and they work great, but look like heck.
Bought some strange looking HOB's on Ebay called Sandman's from Wardley's. They have a fluidized bed chamber, a small fish friendly floss batten prefilter and a final chamber that comes with a charcoal pad. They're a cool blue color with a black lid and they move a fair amount of water (rated for 38g. for what that's worth). But that's not the good part. With shipping I think I only paid about $12 a piece for them. Another cool thing is that you can replace the stock media with all sorts of different combinations. I've got a 100ml bag of Purigen in the carbon chamber and a piece of reticulated foam behind the floss batten pre-filter. You could easily drop a bag of carbon or whatever in there as well. Just hooked them up on some 15g. cory tanks so we'll see.

These are some older unsold designs I believe 'cuz I've never seen them anywhere so parts are probably non-existent, but I'm pretty sure I can find an impeller that will retrofit somewhere. Even if I can't...if I get a couple of years out of it I'm still way ahead. Heck put a pair on your 30. They actually move a good bit of water and come with an outflow diverter that you can use to direct the outfall off to the side instead of straight down toward the bottom, and the intake, like traditional HOB's.

If you don't mind the beefy looks Ken's Fish has 150w. metal Guardian heaters for $14. Stay away from the Chinese glass ones. I haven't had very good luck with them at all. If you use the two cheap HOB's you won't need a power head unless you're raising trout. There are some others on here that have had good success with Aqueon HOB's too and they're also pretty cheap.

Of course there's always the bubble box with floss and charcoal. Lot of my breeder friends use them in abundance. As for looks...well, they've got a real nice personality.