Grab yourself an AquaClear 50 or 75 (or two, if you're filter happy). The Walmart Aqua-tech is basically a knock off of the AquaClear line, right down to the basic look and function, with the exception being that the AquaClears use proper filtration media, instead of a thin, hole-ridden sheet of mesh.
If you've got an established cycle, I'd recommend putting the Aquaclear on with the walmart special for a few weeks to allow the bacteria to migrate to the new filter, then remove the Aquatech.
The Aquaclear propaganda tries to tell you you need Activated Charcoal and an Ammonia removal packet. Toss that away and buy a 3 pack of the Aquaclear foam inserts meant for mechanical (1st stage) filtration, and just run 3 of them at once. The media cradle is designed to take any combination of 3 Aquaclear filter inserts. At last count they have:
1. Foam block (for mechanical filtering)
These blocks, just a thick rectangle of foam, are meant to catch the chunks and give the beneficial bacteria a place to call home. They are the most important stage, and the only one you need, so run as many of them as you can
2. activated charcoal packs
These bags of charcoal will remove teeny particles and impurities from the water. If you have cloudy water, discolored water, or are trying to pull medications out of the water, run one of these, then throw it away when the problem has been fixed.
3. ammonia removal packs
These are ammo-lock packs that convert ammonia into something more stable and lock it into the pack, so you can dispose of it every month or so. All they do is keep the proper cycle from happening, starving the good bacteria, and starving plants of the bacteria's product, nitrates, which they need to, you know.. live..
4. zeo-carb packs.
These are a combo pack combining ammonia removal and activated charcoal. Since you rarely need the carbon and never need the ammonia removal, skip these packs, too.
5. Bio-Max packs.
These are a bag of highly porous ceramic chunks, each of which has some ridiculous amount of surface area. They give an excellent place for even more good bacteria to live, but provide little in the way of filtration as the foam blocks would. If you're running two of the Aquaclear filters, which I personally recommend (more on that later), then you may want to try out running 3 foamies in one filter and 2 foamies and a biomax in the other. That's how I'm running my 30g tank right now.
Cleaning the AquaClears is simple, too. Simply remove the lid, pull out the media cradle, and rinse the cradle and your foamies off in a bucket of tank water (not tap water, as the chlorine will kill all the friendlies living in the foam). I tend to lightly squeeze the blocks out in the old water when I'm doing a PWC, and you can really see the work they do then, as the water goes from slightly discolored to horrible. Then just put the blocks back in the cradle, change the order up if you want, in order to make sure they all get a chance at the bottom, then slide the cradle back into the filter.
About once every month or so, I'll take the cradle out, unplug the filter and pull the whole unit off the back and dump it out in the PWC bucket. That way, any bigger bits that didn't go through the screen into the foamies gets dumped out. With me, it's usually little leaves that fell off my Moneywort that get sucked up the intake, but never make it through the cradle's wide screen into the foamies.
The numbering on Aquaclear models changed recently (couple years ago). The models used to be numbered by their GPH rating. So the Aquaclear 150 was rated at 150 GPH, etc. They've changed them to be more neophyte friendly, so now the former Aquaclear 150, a good choice for a 30Gallon tank, is now called the Aquaclear 30. Makes sense, as a good filter to tank ratio would be if your filter can turn over your tank about 5 times an hour.
The problem comes in the fact that the AquaClears measure their GPH rating with no filter media in them, so a 150GPH filter, with 3 foamies in it, might only turn over 100GPH, or less. That's why I recommend running two. They're nearly silent once they get primed (full of water) and they're relatively cheap. There's no reason not to, unless you have seriously current sensitive fish or plants (or fry that might get sucked up, in which case turn the flow down until they get big and strong enough to fight the current).
For your setup with the AquaTech 55 Gallon setup (I have the Aquatech 29 Gallon setup), I'd probably recommend getting two Aquaclear 50s, or one now, and think about another down the road when they go on sale. You might also look at the Aquaclear 75, though I'm not sure if the HOB filter inlets on the back of your canopy would accommodate, though I suspect they would without problem.
On that note, I just realized that I've written a full page of text about the ins and outs of aquaclears.
