now that's a new one on me
Under couch sump - I gotta hand it to you - very creative - sort of listen to the water gurgle as I drift off for a nap LOL.
Anyways - yeah that looks like a good design, especially the slits in the vertical drain tube - never thought of that as an option - learn something new every day - give me an idea to fiddle around with too - thanks !
The sump is nice - sorta pricey but still very nice and I can see why someone would buy it.
The sponge bubble trap filters are nice, but need to be cleaned often if going reef tank - but that's cool - just another thing to clean though. Although some claim you can actually promote some denitrifying bacteria in these sponges, I have no experience doing so.
Either way - still okay.
If you have your return(s) vented at top surface of display tank - and don't get a lot of back flow to the sump upon power loss - a smaller sump is do-able, but you have to tinker with it to safe. As Ed implied - Bigger it better with sumps too.
For my money ( near $300.00 bucks for an acrylic box with baffles, bulkheads and fittings - I'd prefer to DIY. But I had stuff left over from an old wet/dry I could canibalize, so it was cool.
Thanks for showing this sump - gives me and others here some ideas too.
See ya !