Let’s talk flow in a peninsula tank!

[fox0521]

Hey folks,

I’ve got a 2’x2’x4’ 125 gallon peninsula tank. I don’t have it set up as a peninsula, but I got a great deal on it so I couldn’t pass it up! I’m struggling to get flow that doesn’t leave dead spots, but also doesn’t super blast my LPS and softies!

Currently using a return pump rated for 2377 GPH (not accounting for head loss), flowing through 4’ of .75” PVC with one 90° elbow at the return nozzles. set to about 75-80% power I believe. Also using an MP40 (help with settings would be appreciated! Turned down to lagoon yesterday at 2500 gph flow) and two Tunze 6045 powerheads (rated for 1175 GPH). One 6045 towards the back, top on the overflow side, and the other is opposite of it, down closer to the sand bed pointed slightly up to accelerate a gyre motion (this is not accurately shown in my picture. I didn’t take new pictures after moving powerheads).

we’ll see how this works, I won’t keep the 6045 on the far end though because of the cords in the tank.

Anyway, what is everyone else doing for flow in a peninsula tank??

 

[footgal]

IMO, the best way is to make a dual return (two flow outputs) on the short side going all the way across the tank. Maybe add 2 more powerheads to buff up the flow but the tank I'm basing this off of is 200 gallons so thats probably unneccesary. Then on the opposite short side, add 2 powerheads blowing directly towards your overflow, this way you create a circular flow around the tank with very few or no dead spots. I would just play around with the flow intensities until you find what your tank needs

 

[Kershaw]

Do you have a canopy? You can run pipes inside so you have a return on the other side as well

 

[fox0521]

I do have a canopy! What size return pump would I need for this? I imagine that the return nozzles closest to the overflow (closest to the return pump) will have much higher flow than the return nozzle at the other end.. hmmm. Any good resources for how to do this? I was thinking of trying to achieve a vertical gyre instead of horizontal.

 

[fragit]

On my tank exact dimensions as yours, I have my return on the overflow side split to two RFG nozzles really close to the surface. (I have a basement sump so I do have to worry about head pressure loss.). With two Tunze 6095s on same side about 6” below surface. I just recently got a Sicce Xstream to see how it is and put it in the viewing end in a corner and can’t even tell it’s there. I’m really liking this new pump and will add another. I tried gyres on both ends for a few years but the maintenance in them was ridiculous. I also had a hard time getting the correct flow with the gyres in and around all my rock work. I also tried plumbing my returns across the top of the tank to the viewing end, I lost too much pressure and it defeated the peninsula purpose for me more so than a gyre mounted just below the surface. My current flow objective is to use my return flow across the top to creat some gyre type action, the powerheads are placed aimed and set to provide flow turbulent flow diagonally across my rock work (left upper corner aimed toward right lower corner and vice versa) on all 4 corners. In my tank the gyres did a good job moving water but were to strong to get flow everywhere I needed without peeling the skin off my corals. More small high power wide flow aimable pumps is the way to go in my experience on a smaller size peninsula.

 

[Ryan Doolittle]

I would put a gyre on the opposite side of the overflow thennout the 40 on the overflow wall blowing across the front. Then another stream style pump that blows bottom corner on the overflow wall across the back to keep detritus from settling back there.

Ideally the return would be on the back corner opposite of the overflow, on a SeaSwirl would be even better. Though I don't see much of an issue the way you have it set up as long as your sump can handle the siphon back to the sump.

 

[HolySmoke]

I would either do one of two things for that tank.

1) gyre left side horizontal centered flowing towards overflow
-mp40 directly below it
-two tunze on overflow near the top but below the gyre flow (Not obstructing gyre pushing surface skimming towards overflow)

2) two gyre vertical position on either side of overflow.
-tunze directly above the gyre (wires will blend in best on that wall as well.
-mp40 on left side as close to center as possible assuming rock work won't eat up all the flow.

They both will work very well for your setup.
Another suggestion is your 3/4" return piping sounds very small for your 2300 gph pump. Pipe size should match pump outlet and I'm assuming that is atleast 1" and most likely 1.25"