Closed Loop Design

[LunchboLobster]

Starting the build for my next aquarium, it'll be a Planet Aquarium 235g (72" x 30" x 25") SPS dominated tank. I'm going to do a closed loop for flow, using 2 x Varios 10 pumps (rated 4200 gpm each) and VCA Random Flow Generators. I spoke with VCA and they recommended 4 of the 1.25" nozzles (the new jumbo line). Probably end up somewhere around ~1500gpm per nozzle. So I'm trying to figure out the right/best configuration of these 4 nozzles for some good random flow. I'll likely connect the pumps to Apex and run some kind of schedule to help with random flow. I plan to have one inbound bulkhead per pump, drilled in the back wall of the tank. For the 4 x returns, I'm going to drop them in from the top (not drill the back wall). I'll have a full hood, so the plumbing can be mounted however I'd like. For return nozzle placement, what orientation would you pick (red arrows being the VCA nozzles)? Any other ideas or guidance? Thank you!

 

[Jarob]

Starting the build for my next aquarium, it'll be a Planet Aquarium 235g (72" x 30" x 25") SPS dominated tank. I'm going to do a closed loop for flow, using 2 x Varios 10 pumps (rated 4200 gpm each) and VCA Random Flow Generators. I spoke with VCA and they recommended 4 of the 1.25" nozzles (the new jumbo line). Probably end up somewhere around ~1500gpm per nozzle. So I'm trying to figure out the right/best configuration of these 4 nozzles for some good random flow. I'll likely connect the pumps to Apex and run some kind of schedule to help with random flow. I plan to have one inbound bulkhead per pump, mounted on the back wall. For the 4 x returns, I'm going to drop them in from the top (not drill the back wall). I'll have a full hood, so the plumbing can be mounted however I'd like. For return nozzle placement, what orientation would you pick (red arrows being the VCA nozzles)? Any other ideas or guidance? Thank you!

I think option 1 personally since they're random flow, 2 and 3 create some wide spaces between the outlets

 

[mfinn]

Here is the hole placement on my closed loop on my 240.
4 bulkheads that have a loc-line y and then split into 8 fans going different directions.

 

[LunchboLobster]

I guess I'm still debating between closed loop vs. powerheads. Seems like nearly everyone now days primarily runs MP-40's and/or gyre's on the ends of the tank. I get that this suits tanks with substrate better. My tank will be bare bottom, so flow from the back of the tank wouldn't be an issue. The appeal of going closed loop was less maintenance (not having to clean wet sides) and keeping glass unobstructed (if I have "floating" flow generators dropped in from the top of the tank). So my question would be, for an SPS tank, with hopefully large colonies one day, what flow pattern will help keep them detritus free better and happy? Flow from the ends of the tank (MP-40's), creating turbulence in the middle of the tank? Or flow from the back wall (closed loop), creating circular flow back to front at the top and flow front to back at the bottom?

 

[Sean Clark]

I like option 2

 

[Maxx]

I was really impressed with this design of closed loop. Not cheap, but long term effective and reliable.

 

[mfinn]

I guess I'm still debating between closed loop vs. powerheads. Seems like nearly everyone now days primarily runs MP-40's and/or gyre's on the ends of the tank.

Who cares what "everyone" does. Not everyone has jumped in.
It's what you need/want.
A closed loop with loc-line on the inside of the tank is extremely adjustable with the ability to direct flow in many different directions at once.
Do a combination, a hybrid of sorts.