Question 2, water flow and designs for reef tanks

[DanG]

More flow is good, but if it should be balanced. There's little point in having 5000gph through the middle of the tank and a bunch of dead spots that allow nusiance algae to grow. From that point, a closed loop running 6 or 7 outlets would be a good choice because you would be able to direct some of the flow.
Newer powerheads are a good choice for smaller or non drilled tanks because they can produce a lot of flow (tunze nanostream) with very low power.

[littlesilvermax]

I use a 6000gph pump through an OM 4-way. Love it.

As the corals grow I find I keep having to adjust the flow. Now that some of the corals are as big as a football I am noticing the odd dead spot.

[Reefer Rob]

I'm in the simple is best phase of my reefkeepng, (who knows whats next) Two MJ mods at either end of my 72 pointed at each other gives me lots of random flow.

[Aquattro]

I'm using 2 Tunze streams in my 75, each at opposite back corners point diagnally across the tank. This give me oe dead spot which is a bare patch of bottom, so when I do water changes, I siphon the crud from this one spot.
I also have about 600gph from my return in a sea swirl, but that much flow from a 1" pipe is amost nothing.
One thing I notice is that the corals that are closer to the direct stream of flow tend to grow faster than others with less flow.
It also gives the fish some exercise when swimming around mid tank.

[rickjames]

I also run two tunze streams in my 150, a 6100 and a 6080. Now that the corals are growing in I could see myself adding some more flow.

I also backed off my return pump from 750gph to probably only 400gph and I have noticed my skimmer has been taking out more gunk, since it ends up recirculating a lot of the water in the 75G sump.

Tunze streams are probably still the best way to go IMO.

[kwirky]

I'm running a seio 1500 on one end of my 4' 120g, and i have ~500gph coming back from my sump flowing across the tank.

I would like to down the road get more powerheads to distribute my waterflow.

Advanced aquarist found that bleached corals have a higher chance of recovering when kept in higher water flow, and that they grow faster in too high of flow than too low of flow.
link here: http://www.advancedaquarist.com/2006/8/aafeature

I have to vouch for that. I accidentally bleached two toadstool frags (Albert was right lol ), and when I moved them to very high flow areas, they returned almost overnight.

Learn as you go...

[reeferaddict]

I have 2 Tunze 6100'sfor main tank flow, 2 separate closed loops on SQWD's for surface agitation, and between 5 and 600 gph on my return on a Sea Swirl, and 2 Seio 1100's blowing the back side of the reef... Somehow the sand doesn't blow all over the water column, but the flow patterns and the Engineer Goby make for some interesting shifts in the "dunes" at times... As things are beginning to grow in and take hold I know I will be adding more though. I'm looking at those 6055 Nanostreams to put on my 7095 controller with the 6100's.