I have a "river-ish" tank without the manifold. I didn't want to totally commit, lol. I have a 55g with 2 AC 70 HOBs & a Maxi-jet 1200 powerhead. I have sewellia lineolata, gastromyzon ctenocephalus, stiphodon gobies (though these are dying off), Vietnamese whiteclouds (almost gone now) & leopard danios. Tons of plants, unlike many river set ups.
What fish are you thinking of keeping? My sewellia have bred a couple times with a few survivors & no effort on my part.
Panda garra, dennisoni barbs & botia histrionica in a different 55g but same filters & PH, 1 of my favorite tanks ever!
With a 180g you have so many cool options! & then there's Mattenfilter variation on the Martin Theone manifold system too.
Loaches are my favorite fish!! But there are many ways to keep them happy.