Fluval 306 canister, outlet options

[Milliardo Peacecraft]

I currently have a 75 gallon aquarium and I'm debating on what's the best option to use for the outlet, the standard outlet nozzle that blasts across the tank or a spraybar that slows the flow down.  I like how the standard nozzle moves the water around the tank so there are fewer dead zones, but I suspect most of my fish would prefer the slower flow of the spraybar.  The exception being my platties, they seem to like to play in the flow riding it across the aquarium and doing laps.  I have a fluval heater about half way across the tank tipped at a 60 degree angle so the water shoots sideways across the tank, hits that and then is diverted upwards over the heater.  The fish basically hit the current and ride across the tank and then upwards over the heater before dumping out the other side.  Some nights they make laps over and over playing in the current.

For those of you with canister filters, what sort of outlets do you use, and why?

[Guppysnail]

I run a bunch of the 07 series which are very similar to the 06 series. I tried a few of the spray bars. Rather than softening the flow each hole on the spray bar became like a pressure washer. It also kept small particles suspended in the water column from sweeping off the floor but not directionally towards the intake  they swirled  

One of my guppies was playing in the flow and went over the spray bar. It blew him up and he hit the lid. I lost him. Had I not seen it I would not have believed it. They also sweep every particle of mulm to the back of the tank where it’s hardest to clean. There were also no soft spots for fish to rest and if you intend breeding fry did not do well for me with spray bars. 

Other tanks I tried aiming it at the back wall.  It was better but excess splashing and midwater/ top water was still so an algae farm on tall plants. 
 

I tried pointing them down a bit. My plants along the back did not like it and I did not get a lot of water movement. Mulm built up. 

so I drilled the holes larger. Then I drilled more holes. 
Once the flow toned down then it was not enough to get motion to the floor. 
 

The end result was 5 spray bars going in the trash after 6 months of constant irritation. 
 

Now the only time I think about my canisters is when the flow slows and it’s time to clean. The normal outflow I love. 

[Pepere]

I have the spraybar across the back of the tank.  It is below the water and aimed slightly up to disturb the water surface.  
 

It creates a circular flow across the top, down the front and across the bottom to the back and back up.

The fish didnt take long to figure it out.    High flow near the top, and down the glass front, but fish swimming an inch away from the glass seem unaffected…

 

The rest of the tank, center core,  is relatively quiescent.  Gentle swaying of vegetation…

I have two wave makers that run when CO2 is running to help mix co2 bubble across the width of the tank.  Before I put those in the bubbles were in suspension  in roughly 1/3 of the tank.

 

The fish like to surf in the current from the wavemakers too..  And they know where the calm spots are…

 

When I get a 75 gallon I am planning on getting more flow from the canister filters rather than relying on wavemakers to minimize the visual clutter of the wavemakers.  I am thinking maybe two canisters, and maybe 1 with the spraybar, and another with a nozzle,,, but I will worry about that more when I get there…