Alternating Gyre Flow Via Streams?

[ebayes11]

I'm in the process of putting together a 140 gallon tank (4' x 2' x 28"). I flirted with a closed loop manifold or ocean's motions permutation, but after learning about the gyre flow, I've decided that that is what I want to replicate. However, I don't want to have a permanent uni-directional gyre - I want it to alternate after sustained intervals. In order to minimize power requirements and external noise I have decided to use either Tunze streams or Vortechs. My inclination right now is to go with Tunzes, but I'm not set on it. I have a few questions to this end:

- Is this possible to create using only two pumps
- Has anyone done something similar?
- Does the controller capability enable me to set up these intervals?
- Will only one pump be able to get the water mass moving quickly enough to generate the desired velocity? (The other pump operating at a low output until the direction changes)


This will certainly not be a conventional vertical "gyre" tank, but the flow will be similar. My primary concern with this is that I will not able to generate the necessary flow velocity with only one pump running at a time.

Thoughts from the Tunze experts?

[rvitko]

OK, before you mentioned it I had never heard of Gyre flows. I have a 5 minute google search education at this point and while I doubt it is possible to fully simulate this in an aquarium I think 2 pumps would give a reasonable proximation, I don't know if anyone has done anything similar though it does sounds similar to the results and conclusions presented by Ron Shimek at Macna last year. The controller allows for intervals as long as 12 hours. I would keep in mind that not every coral will be from a zone where this gyre flow will be the predominant flow, it sounds like it would be the dominant flow on deep reef slope dominated by soft corals, anemones, gorgonians and that it would be less influential in shallow reef areas such as the SPS dominated reefs that are in surge zones and washed by waves and even exposed at low tide.

[ebayes11]

Roger,

During the up to 12-hour long intervals on the controller, is the pump operating at full power (or the maximum power I specify), or do I have the ability to have it pulse, etc?

I would agree that this flow type is likely not indicative of natural flow phenomena on a reef crest, but I would think that it could be relatively representative of an inner reef edge habitat that is characterized by tidal flow.

While I've seen numerous examples of the gyre flow concept using closed loops, my preference for using streams or vortechs in lieu of a closed loop is that if the gyre concept proves less than ideal, I can modify the position of the pumps to create a different flow theme.

To recap, you think that it would be possible to create the gyre flow using only two pumps (using only one at a time to create the uni-directional current)?

[rvitko]

You can pulse it, or have it run at a constant flow, the other pump can be off or idling at 30% power.

Yes.

[ebayes11]

What size/model or other hardware would you recommend for this set-up?

[rvitko]

I would either get 2 6101 or 2 6201, 2 6201 would give stronger flow if that is what you are after.