Ya know I have thought about this quite a bit. On my 190g I have a closed loop that is powered by a sequence hammerhead and then through an OM 4 way. I also have 2 X Tunze 6200 on a controller and then of course my return pump for another 900 or so gph.
On my 230 I have a closed loop run with a Mag 24, 2 X Tunze 6100 on a controller and again my return pump for another 900 or so gph.
I don't think I have enough flow in the 230g for SPS but it is mostly softies anyway.
On the 190 - if I were to do it again I would skip the closed loop and just have my return and 4 X Tunze 6200's for flow. The flow of the Tunze - particularly run off of a controller IMO just can't be beat. I might even add a couple of tunze waveboxes to this setup to get the rolling water movement.
If and when I ever set up my 300g cube I am not going to do a closed loop. Just 4 or maybe 6 Tunze's.
I am probably going to re-do my 230g this winter and am going to suck out the DSB and put another couple of Tunze 6100's in there and may add a wavebox as well and turn this into a SPS tank. My green carpet anemone has snacked on all of my gobies so I just have to probably find a new home for my black cucumber and watch the 2 mandarins to make sure they are getting enough to eat.

This is a good point. All too often it seems we are overly concerned about gph , adding ph after ph trying to get rid of dead spots. If the ph's are pointed towards each other you'll end up with a swirling type flow, although somewhat random it dies out quickly, The flow from the ph's essentially cancelling each other out. The newer ph's on controllers avoid this if set up to do so. After talking with Paul at Oceansmotions about my closed loop I decided to have my sump return(Dart) over the top split into 4-3/4" returns aimed down the back towards the bottom. Then 4 cl openings on the back wall near the bottom shooting water towards the front. 3 cl openings on the bottom about a third from the front shooting water towards the top front glass. This water bounces off the top eurobrace, back toward the rear of the tank and into the overflows. One more cl opening on one end. This one I'm still experimenting whether to have it aimed directly towards the opposite end or towards the top front rebounding toward the back. Almost all the rock is on pvc racks enabling the flow from the closed loop on the back to shoot under the rocks towards the front. The cl is on a Oceansmotions 4-way and Barracuda. So far I like this set-up. There are no areas that are blasting 24/7 but rather large amounts of water moving in concert with each other in alternating patterns. It takes about a week before there is any noticeable collection of detritus on the BB and then only in a few spots, which is easily vacummed out. The tank is 375g 8'x30"x30"

I have read multiple times from respected marine biologist types (Calfo et al.)that flow is second only to water quality in importance in a closed system. It makes sense really that in order to deliver nutrients etc that are in the water collumn you have to have good flow... I currently run a Dart on a CL with 4 outs 2 on the bottom pane of glass directed at the front of the rockwork and 2 on the back pane blowing behind the rockwork (soon to install the PVC rock rack)... return from the sump at about 900 Gph after head blowing at the surface for aggitation and finally a Tunze 6100 on a single controller... I notice way better polyp extention than I had ever seen when these corals were in my old 75 with way less flow (2 months ago)... furthermore I have the Tunze pointing toward one end of the tank and the polyp extention is greater on that side of the tank, which makes me believe that the corals are happier over there... time to ask the wife if I'm allowed to buy another 6100... oh and then a multicontroller... oh and then...and then... I wonder why i'm always in trouble?? :wink:

Regarding those 6100's......I take it they have to be run off a controller to take advantage of their variable speed control feature?

Thanx much,

Yes the 6100's have to be run of a controller - it is whether you go to a single controller or a multi (up to 4 powerhead) controller. I have only used the multi controller and have never really investigated the single controllers.

So how the heck does that work? A controller varies the amount of juice going to the 6100?
(I don't mean to get off topic, but I don't get the whole controller thing. :redface:. Seems that they monitor parameters, but do all this other stuff too? Like a fancy powerbar, and more? All very confusing:confused:.)

Thanx much,

Oh man now you are going to get me confused:scatter: There is a specific controller that you get for the Tunze streams - it just depends on if you want to only control one powerhead (single controller) or more than one (multi controller) They basically can be set to control the amount of juice (flow) that the powerhead has as well as have it turn off and on at preset times intervals.
These controller only control the Tunze powerheads and not all that other fancy smantzy stuff. Those controllers I know absolutely nothing about.
Here is a link to a 6100 with a single controller.
http://www.jlaquatics.com/phpstore/s..._ID=tz-ts6110k

Go
 

For a totally different perspective.
I use a closed loop that attempts to deliver laminar flow to the entire length of my rock walls. I created the system for seahorses as they don't do well in the focused blast of powerheads. Bear in mind that it is a softie oriented reef and I don't keep SPS. The idea is an adaptation of the UGJ's used in big cichlid tanks.

I run 2 M.J. 1000's in line connected to about 16' of 1/2" PVC. This is laid out beneath the substrate along the front and back of my rock walls and drilled every inch with 1/8th holes. When I tested the system I had surface agitation across the entire surface of my tank (straight up from the bottom) and it has worked well so far. The "mini jets" are constantly kicking detritus up into the water column to be siphoned off by the horizontal overflow.
I don't run any power heads and the only other flow is moderate surface flow from my returnline.
I'll try to post a pic or two.

http://i35.photobucket.com/albums/d1...r/100_0907.jpg

http://i35.photobucket.com/albums/d1...r/100_0948.jpg

and a year later (I am slowly siphoning the substrate out to create a B.B.)

http://i35.photobucket.com/albums/d1...r/100_2200.jpg
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Suzuki RV125

Thanx for the reply. Inevitably, I’m still a tad unclear on how these work (or more accurately....what they do, in this case).

So, I took the term “Variable Speed Control” to mean that if this PH (6100) is plugged into the controller, and that controller is programmed, that the PH’s flow rate would fluctuate throughout the day (and night) independent of any further fiddling from the aquarist. Now I’m thinking this assumption is incorrect. Am I now correct to assume that the controller is not programmable, so to speak, and that if I were to want to change the rate of flow of the PH that I would have to adjust the controller each and every time?

Also, other than during feeding times....what is the advantage to having the PH turn off?

I’m wondering if I can justify the cost of a 6100 PH and a 7091 controller when that combo costs just as much as two 6080’s.

Thanx much,

Calfo manifolds are among the best if you can fit them...

http://www.canreef.com/photopost/dat...ragtankTop.jpg
Normally one would use locline to get some nice random flow, but in my case, decided since I had 4 Hydor Flo's kicking around, they'd do just fine (they clip nicely into a 1/2" FPT fitting).