Flow for NPS reef tanks

[sammy33]

Since we have a feeding thread I thought I would get one started on flow for NPS tanks.

I seem to keep seeing recommended flow rates of 8-10cm/s for dendro/sclero. This equates to somewhere around 4 inches per second of flow. Since most all pump manufacturers specs include a basic gallon per hour rating to quantify flow - how do we choose pumps?

I wonder if measuring flow is as simple as dropping some flakes or other floaty in front of various powerheads and measure the distance travelled in one second to find which one genrates these flow levels?

Seems that the propeller style powerheads producing the wide patterns may be the way to go? Maxijet style powerheads can likely produce the flow speeds (?) but the pattern from a Tunze stream, Koralia or even a maxi prop-mod would likely be better with the wider dispersed flow patterns.

What about smaller tanks? It would seem logical on a 24" wide tank (front to back) to place two maybe even three Vortechs on one side to create the laminar flow that these corals seem to prefer. In a smaller tank like say a 20 long that is only 12" wide what do you use for flow? Maybe even a custom setup with a large spraybar style return on one side and the overflow on the opposite side?

 

[Kolognekoral]

Sam,

good general topic!

I use a variety of pumps and power-heads for current. There is the main circulation pump for the filter, which creates a figure 8 type flow by crossing diagonally through the tank. As my tank is quite high, around 70cm/28", this created a three dimensional circulation that comes through the rockwork, which are like a jutting wall. The tank is viewed from 3 sides.

Additionally, there is a Tunze 6080 at one end to create a strong laminar flow which feeds the other circulation. Still another small powerhead is deeper to help pull stiller waters from behind the decoration on the 4th side. This creates a strong jetstream where I place strong current gorgonians.

I have found that the general 8-10cm per second is just that, general. Some gorgonians require a much slower flow to properly catch their prey, while others, mainly the very fine-polyped types, seem to only open at extremely fast current, say 15-20cm per second.

All aquariums that contain obstructive decoration will have a variable turbulent flow. This allows one to place varios animals in prefered current rates. Most of these rates are too fast for many SPS, which do not open their polyps fully. They do prosper, however. I estimate flow through various parts of the aquarium with food drift. Fine eggs are easy to observe and follow even small currents.

From my observations I have grouped animals into low flow (this is relative), 4-8cm ps. , such as Tubastrea, Diodogorgia and other large polyp gorgonians, medium flow 8-12cm ps, for Scleronephthya and Denronephthya and fast flow 12-20cm ps for fine polyped gorgonian.

I have yet to work with Hydoid NPC, therefore wonder what they require. I suspect most are in the middle, as they are often seen together with Dendros.

What have others experienced with their animals?

 

[sammy33]

I have a mostly tidal laminar style flow in my 125g reef tank. I have two powerheads on each side with one on the side wall and one on the back wall pointing to the other side. I have the ones on the side walls on constantly and the ones in the middle on a controller. Here is a pic so you can get a visual going:

This configuration works well as the flow ends up less turbulent with other things I have tried but I think I am losing a lot of energy with the opposing powerheads on the sides. The flow from each is "pushing" against the other. This creates almost a still spot in the middle where particles just seem to spin around in place.

I would like to get two more Nano Streams and then place two powerheads on each wall. I have the multi controller so I can control them and have only one side at a time pumping. This would likely give me much better flow speeds without any opposing flow. I have tried this with just a single nano stream on each side but it is not nearly enough flow for the SPS in my system.

I have some smaller 25 gallon tanks plumbed together with a common sump-fugium that serve as a frag system and QT. I have one tank on the end that is currently empty and just has system water flowing through it. This frag setup may be easier to experiment with dendro/sclero than converting my reef tank. This is an older picture as the tank on the right is now empty:

I am wondering if I can still get the flow speeds in these small tanks? These are 24L x 18W x 12H. This makes them very easy to light but lighting is not as big deal in an NPS tank. Would a couple of Koralia powerheads on one side work? Would it be easier to optimize the flow in a longer/larger tank like maybe a 55g (48L x 13W x 20H)?

 

[Kreeger1]

Laminar flow, 7 inches per second for flow speed, power heads or returns on one side of the tank. Random pulses for those power heads. That would be my ideal setup. Not the eastiest thing to do though on a 8 foot long tank.
I added a few power heads to the middle of my tank, going with the laminar flow but sort of at a 45 to 65 degree angle.
Seems to work
Erik

 

[sammy33]

<a href=showthread.php?s=&postid=12030081#post12030081 target=_blank>Originally posted</a> by Kreeger1
Laminar flow, 7 inches per second for flow speed, power heads or returns on one side of the tank. Random pulses for those power heads. That would be my ideal setup. Not the eastiest thing to do though on a 8 foot long tank.
I added a few power heads to the middle of my tank, going with the laminar flow but sort of at a 45 to 65 degree angle.
Seems to work
Erik

I think the 8 foot tank would be equally as challenging with flow as a small system. The longer tanks may have an advantage over the shorter tanks. At least a Stream 6101 makes more sense in an 8 foot tank than a 2 foot long tank.

I guess I need to put some powerheads in my 24" tanks and simply measure the flow speeds. I will try to come up with some way to measure the flow in inches per second. I guess I can set up a video camera, tape a ruler to the front of the tank and throw in some oyster eggs or maybe cyclopeeze to measure the flow? I can then watch the video and extrapolate the flow measurements based on frames per second.

I would like to establish some standards for referencing flow since seemingly none of the powerhead manufacturers publish flow rates in inches/second.

 

[Stottlemire]

The easiest way I found to measure flow was, a turkey baster with mysis shrimp in it and a ruler taped to the glass. Drop in the mysis shrimp and use a watch to time the distance traveled by the shrimp. Ideal is between 7-12 inches per second. The real problem is trying to keep the flow after it hits the first dendro.
The 7-12 inches per second is for dendros and scleros and most small polyped sea fans also criniods. My dendros do not do well in turbulent flow, they seem to like one direction at a time.

Chuck

 

[reef_research]

Why not gyre?

Why not gyre?

If you are looking for laminar flow, why not try a gyre tank? Public aquariums, notably Hawaii, have used systems like these for large gorgonian colonies with great success (fraggable specimens, visble growth enough for research requirements). The setup mimics the ideal "reef slope" or continous directional flow that you may be looking for.

http://www.advancedaquarist.com/2007/1/aafeature#h5

Enjoy, and good luck!

 

[sammy33]

A gyre is a great idea. I have fumbled around some ideas to create a gyre with live rock acting as the shelf or divider component of the setup.

Has anyone ever done this in a short tank is still my main question? Is there a tank length that is optimum to create the preferred laminar flow rates?

 

[dendro982]

If I may:
in a short tank more or less laminar flow could be created:

- by placing powerhead in back top corner, with flow flattener (the triangle thing at the end of Maxi-jets or LockLine) directed in the front lass, where it will be reflected on the side glass, then on back glass, creasing almost laminar flow around the central mass of the LR. Nano-cubes have it built-in.

- vertical from top to the bottom flow can be created:
-- in hexagon - by hanging on the powef filter. Water crosses the top of the tank, reflects from the back, flows around the central mass of LR, reflects from the sides, and returns to the top. I like the relult.
-- in rectangular tank: two power filters, in opposite corners, give rotational effect. If on the short sides - side flow, if on long sides - top to the bottom flow.

Can anyone post pictures of their systems? With sources of flow visible (or tell where they are, if they are hidden).

 

[reef_research]

Sammy, it might work even better in a shorter tank. A small problem with longer gyres (easily remedied by powerheads) is that minor flow reduction zones can occur along the middle of the dividing wall. With a shorter tank, you may actually escape having to correct for this, in addition to needing less powerheads to create the laminar effect.