Hey, all new questions great!!
I generally do things really slow with my setup. So right now I only have one of the channels with frags in it, about 6 of them(yeah, I know...don't put too many in there now
). Nice thing is the raceway is huge and I can probably fit 120-150 frags in the thing easily. I've been playing with mounting them, making sure the lighting is working out and observing flow.
Now that I have it set up, at this point I'm not really worried about the linear flow, I see the coral polyps whipping around a lot so the flow is a little turbulent.
stranglehold
What about putting little 1 or 2 inch wings in the channel installed vertically and at a angle slightly greater than 90. alternate sides of the chanel with every wing. This will cause the water to bounce back and forth and create some swirling and eddies too.
That would work. It might take space away from frags though. But if it could be removable it could be something to play with. I thought about something close to this. I just haven't thought of a way to mount it in the tank.
Mine will just be up and back 30". Basically a U with a total length of 60" and I am going with 4" wide. Maybe a little wider if I can fit it in my design.
I would stick with 4", mine is 5" and I would not go any more than that. The narrower the channel is, the quicker the flow will be through it.
melev
Hi Marc, There is no powerhead in the raceway. All flow is from the overflow of the refugium, so there are no pumps what so ever. I'm pushing maybe 800-850 GPH through it.
I nice thing about this way, is you don't have any of the problems that a powerhead gives you. With a powerhead if you have too much in front of the pump the flow will be blocked and everything behind it suffers. With the water coming from an overflow the water
has to go somewhere. Because there is so much water coming into the tank, the flow actually gets stronger behind anything blocking the water flow. So there are a few benefits, as the frags grow the water flow will not slow down but speed up, because the water is now being restricted and forced to flow into a smaller area, sort of like putting your finger over the output of a garden hose.
But in the end, I'm not sure how much of a problem linear flow will be. The flow is definitely not just in one direction. Observing the polyps at night they don't just all point downstream. They do seem to blow haphazardly every once in a while. But time will tell on this point in the end. It's really not a big deal to rotate the frags. I could just pick up the whole eggcrate tray filled with frags and rotate the whole thing once every week or two, if it came down to it.
Here is one piece that I would do a little differently in the future and I'm still experimenting to see what works best. At the end of each channel I have a U turn. I would make this either smaller or no U at all. Right now the flow is not that turbulent down the channels. If I extend the wall out to leave only a 2" gap, rather than 5", I get a lot of turbulent heavy flow down the rest of the channel. Right now I have extended the wall, with a piece of acrylic, all the way to the end and lowered the top so only the top 1.5" is open for water to flow through. I am getting really nice flow in the channel doing it this way. But I'm still playing around. I hope that makes sense.
