Yeah for sure. It's a "diy overhead sump". Think it originated from Joey (king of diy) on YouTube, but if you Google it you'll see a lot of pics and vids of what others have done with the concept. Most people use a planter box but I measured the inside or my canopy and found something that fit. My thoughts are just as yours, any extra filtration helps. I ended up using stuff from what i had at the house, with the exception of a few things. The pot scrubbies I bought at the dollar store. I think I used about 10 packages worth in my container. Vinyl tubing and drains at the hardware store. You can find the egg crate light diffuser there too.
I used a power head that i had by marineland. I think it's their biggest model. I used 1/2 ID vinyl tubing which fits the power head output and some 90 degree elbows to get the water to the filter. I notched the container a bit for the elbow and use zip ties with mounting blocks to secure it to the outside of the container. I started with two drain holes also about 1/2 diameter and tested the flow. I ended up adding a third drain hole which was perfect for the flow of my powerhead.
I used egg crate light diffuser panel to make a compartment for the filter floss. You can add extra compartments if you want to run different media. I fitted it to the container to be a tight fit, then drilled holes towards the top of the container (higher than the water level) and zip tied each side for extra security. I also used the egg crate to secure the pot srubbies down. Some people use lava rock as bio media or whatever you prefer. I like sponges. Whatever you use you don't want to risk it plugging up your drain holes or you'll have a big mess. Drill some extra drain holes above your primary drains just in case. My primary drain holes are just high enough to fully submerge the sponges leaving about 2" to the top of the container.
I ended up adding the plastic cup cut in half to catch a little bit of water that was splashing off the filter floss.
You can really invest as little or as much as you want in this. You'll see on google that some people have some pretty elaborate setups. I wanted to go with low flow. I noticed a lot of bio media and nitrate reactor type media prefers slower water flow, and with this not being my primary filtration I decided on going that route. You could also use an adjustable water pump off ebay or amazon if you don't have a powerhead laying around.
In the end I'm willing to bet that this little thing will have more beneficial bacteria that my HOBs and canister filters. I also love how accessible the filter floss is so I can change it out often.