Update:
Pump and stuff were home earlier than I expected. Thanks Marine Depot for super fast free shipping.
Sicce .5 pump perfectly fits in the back of the returning chamber. The pump still has a little bit of space around to move around and for water flow. Very strong and deadly quiet.
IM spinning stream works very well as rotating and water movement. No noise as most reviews said so. Maybe I got lucky.
Tank has been wet, and everything looks good so far. I still see tiny bubbles coming from sand bed and return pump. I guess since everything is so new, so they need time to break out. Even though I set the pump at max level (185gph), I still see not a lot of flow in the tank. Unless, when spinning stream breaks the water surface. Maybe corals will tell me that is enough flows or not later.
Putting the filter sock in there to clean out dust and debris. Tank water has been very clear after filling up. Maybe I washed the sand too well, lol.
Here is the FTS:
Thank you everyone for the feedbacks in the last couple days. I really appreciate that.
Trung