Koralia 3 or 4.

[SeaMac2]

I have 2 Korallia 3s running in my 75g with two Mag 5 return pumps and honestly I wish I had more flow. I'm only keeping softies, LPS and the hardiest SPS (Montipora caps)...I would think that acros would like even more flow. YMMV.

 

[LockeOak]

I have two K4s in my 4' 50G. They're in the top opposite corners, one blowing down the top center of the tank and the other blowing down across the bottom, forming a cyclical flow. The return pump doesn't add a whole lot, maybe 200gph.

 

[Tajjo]

I have 2 3s they are perfect.

 

[mile sq. reefer]

I guess I'll go with 2 K4's. Thank you all for the help and information. 2400gph will give my tank the proper flow it needs as it matures without the need for another upgrade.

 

[Logzor]

I have a 55 4' with two K3's and one K4.

I have one of the K3's devoted to blowing behind my rock work. I keep my softies towards the bottom and sps on th top. No problems.