Flow advice please

[NateHanson]

I'm trying to work out a new flow arrangement in my 65g SPS tank (36"x18"x24"h).

It has a left corner overflow with about 800gph from the return on a pressure rated pump. There's a Seio 820 in the rear right corner pushing another 800g, but much more gently than the 3/4" return.
There are two closed loop outlets low in the back of the tank, with a mag7 and non-functioning SCWD.

I'd like lots of chaotic flow, but dropping $125 on an Ocean Motion or Sea Swirl is not an option. How would you suggest I setup my flow for maximum chaos without throwing sand everywhere?

Here are some options I've thought of.
-Replace the SCWD with a Tee (I'm sick of cleaning this every month when it jams).
-Put the mag7 on a 15 minute timer, so it goes on and off 4 times/hour.
-Put an eductor on the return pump to broaden and increase the flow pattern, while cutting down on the overflow demands.
-Put a wye on the sump return to split it between two 400gph nozzles, maybe put a Hydor on one (these seem to do ok with about 400gph).
-Possibly not run the closed loop at all. Particularly with an eductor and the seio, I wonder if that would be so much flow that I'd be better off ditching the CL, and saving the 55 watts.

Lets here what you think. And remember - unless you're planning on making a donation, don't suggest a $200 solution. Those just make me drool on my keyboard.
Nate

 

[mikestod]

That was always a dillema with me on the 65g as well. I'm not sure about chaotic flow, but if you want to add some extra you could always take the closed loop outputs and turn them into intakes. You could essentially put a pump on each of the three drilled holes and plumb returns with PVC up over the top of the tank brace and triple your flow without adding powerheads to the tank. If you put them all on timers to run for 30 minutes at a time they could overlap and cause a pretty good cycle.

To be more cost effective, you could take the tee out of the closed loop and run a single line from the intake to one output bulkhead. Then take the remaining output bulkhead and turn it into an input with a straier and and external over-the-top return line as above. That would mean there is one less pump to buy.

Only problem with either of these is that the intake strainers would be a pain to get to with the bulkheads so low in the tank and probably covered by rock.

 

[~Flighty~]

I tried a bunch of plumbing solutions with our tank. We finally reached the conclusion that static plumbing doesn't make chaotic flow no matter how many eductors and outlets and constricters you use. The flow we were the most happy with was one big outlet swirling the water in a circle. conflicting flow just made dead spots, but circular got the water moving and over time would carry the other water with it (if that makes any sense) removing most dead spots and colecting the poop in one place.

 

[Liam]

Nate ,is your pump producing 800gph or is that its max rating,if you are getting 800 at the return then i would say penductor,i have these on the 150 and the move some serious water.I have one on each of my T4's
and for $25 bucks you can't go wrong,no extra running costs either

 

[~Flighty~]

For a more quantatative example about the circular flow, when we tried lots of outlets pionting in different directions food would get blown around, but end up on the bottom very quickly. With the circle setup the food would make 10 or 15 laps around the tank without touching the sand.

We liked this setup enough that even with the tunzes we shut them off for feeding and go back to the circular flow.

 

[NateHanson]

Thanks Mike.
I don't think I need much more flow, with about 2400 gph right now. That's almost 40x turnover. I suspect that if I increased that I'd have to go barebottom.

 

[NateHanson]

Liam, the pump is a genX mak4, producing about 1400 gph at the pump, with about 950 in the tank with headlosses, and I am diverting about 100gph into the fuge. So I think the setup sounds like it would fit the requirements of an eductor. Which eductor did you buy? What do you think are the prospects for DIY an eductor?

Cindy, That's interesting. I can see how that would work. Do you think regular circular flow is good for the corals though? I would think they wouldn't get flushed as good if they always had upstream sides and downstream sides. How important is variation in the flow for SPS?

 

[Liam]

I got the 3/4 inch,black penductors,i forget the orifice size but it think it is the standard.
As regards to diy,i think it could be done if you have a lathe and can get the appropriate material in rod form.
Judging by your diy skimmer i would think you could do it no problem
If you decide to buy them,call KTH sales to order and give them your pump size and make,head etc and they will give you the expected flow and sell you the correct penductor

 

[~Flighty~]

I am far from being an expert on this, but here is my take on it for what it's worth. Strong chaotic flow is the best, but that isn't going to happen cheeply. constant flow didn't seem to really be a problem except for dead spots that don't move food to the coral or waste away. Constant unmoving lighting seemed to be worse than the constant flow. with the circular flow you are constantly adding energy to the spin which really gets the whole body of water moving. Of course, my tank was set up very well for this with the rocks in the center. I don't know if it would work at all in a traditional tank, but get a bunch of 90 elbows and point them the same way and you can try it very cheeply.

 

[~Flighty~]

I have some eductors (or penductors, I forget which) if you want to give them a shot.

 

[NateHanson]

I have some eductors (or penductors, I forget which) if you want to give them a shot.

Oooh! I'd love to give one of them a try!

 

[~Flighty~]

Come and get um or remind me to bring them to the meeting.

 

[NateHanson]

I'll stop by this afternoon if that's ok. Maybe 1pm? Would that work?

 

[~Flighty~]

That sounds fine. If you're stopping at AA on the way, could you pick up a lawnmower blenny for me?

 

[NateHanson]

Sure. How big?

 

[~Flighty~]

I think they hav a few. The one in the clam tank would be good if they'll sell it, otherwise, whichever one looks the perkiest is eating the best and has nice color. I don't think he'll go hungry in my tank.

 

[NateHanson]

ok

.
.

 

[Liam]

let us know how you get on with the penductor Nate

 

[NateHanson]

I will. Picked up a couple from Cindy, and I just need to get an adaptor from HD before I can give it a try.

Nate

 

[NateHanson]

Ok, I hooked one up in the back corner of my corner overflow (so at the back pointing diagonally forward. This thing tears up the water!

The flow pattern feels about 4 times wider than the 3/4" nozzle I was using, and every bit as swift. It's also noticeably more turbulant than the pump return alone. I can't say how much more water is flowing, but it feels as or stronger than the straight nozzle, and the pattern is much wider, so there's probably a few times more gallonage.

It's a bit more noticable in the tank than the locline I had there, as it's about twice as wide (although no longer - I was suprised how short these Penductors are).

I'd like to plumb it over to the other side of my overflow, so it's aimed straight from the middle of one side to the middle of the other side. I think that will make better use of all this flow. Frankly it's a little tough to know what to do with that much water movement in a 3' tank.