How do you know when you have enough current for sps?

[Anonymous]

Supposing two swallows carried it together?

The natural reef features comparably huge volumes of flow at fairly slow velocities. The only way you can reproduce this in an aquarium is by replacing the glass with screen and attaching the tank to the back of a rowboat. So we compensate by using small volumes of water at comparably high velocities. In my opinion, powerheads on wavemakers or seaswirls are roughly the same thing.

Don't point em straight at a coral, and if the sand won't stay on the bottom you're using too much.

 

[Anonymous]

Supposing two swallows carried it together?

The natural reef features comparably huge volumes of flow at fairly slow velocities. The only way you can reproduce this in an aquarium is by replacing the glass with screen and attaching the tank to the back of a rowboat. So we compensate by using small volumes of water at comparably high velocities. In my opinion, powerheads on wavemakers or seaswirls are roughly the same thing.

Don't point em straight at a coral, and if the sand won't stay on the bottom you're using too much.

me too.

 

[Anonymous]

Has anyone "played" with having the sump supply line come out near the bottom of the tank and throttling it back with a valve? Or on a closed loop? Seems like one could achieve a better flow, especially if using largediameter pipe.

 

[esmithiii]

pardon me for being stuck on this, but how do they "do nothing to eliminate dead spots"?

it seems they certainly would. if you put one on each side of a tank and intermittantly turned one and then the other on, this would create a back and forth effect, no?
if they were both on all the time, there would be areas where the flow remained constantly blowing in one direction. turning one off could eliminate "dead spots" by the current switching direction in that area.

In my opinion, powerheads on wavemakers or seaswirls are roughly the same thing.

keep in mind that a sea swirl sweep 90 degrees. A powerhead points in a fixed direction. Imagine a laser connected to a seaswirl, and then one connected to a powerhead on a wavemaker. The laser on the sea swirl would hit a 90 deg. arc while the laser would hit the same spot repeatedly as it is turned on and off by the wavemaker. Obviously this is an oversimplification since the area hit by a sea swirl or powerhead is really cone shaped, but hopefully you can see why I would say that a powerhead (or even 4 powerheads) will have less of an impact on dead spots than a sea swirl.

Here is another thing to think about: Picture a point in your tank the size of a single SPS polyp. If it is in the path of a powerhead on a wavemaker, it experiences a sudden blast of flow that lasts for 10-20 seconds and then nothing. If it is in the path of a sea swirl, it gets gradually more flow as the sea swirl turns towards the point (since the flow is cone shaped with less flow at the edges of the cone than in the center) which increases to a peak and then gradually decreases as the sea swirl passes. This is much like the motion that corals experience on the reef as a wave passes.

Personally I use 2 sea swirls that sweep towards one another. There seems to be no dead spots in my tank due to the sweeping motion. I have a wavemaker that I used for close to a year. I like the motion of the seaswirls much better, IMO. The water movement seems much different than when I used the wavemaker.

Ernie

 

[npaden]

Based on my reading we should be shooting for velocities in a SPS tank to be around 2 ft/sec. Horge did some studies in the Philippines and saw readings as high as 4 ft/sec on a reef flat.

I personally try to use a lot of large outlets flowing medium amounts of water to keep velocities at reasonable levels. A 1/2" sea swirl is rated at 550 gph but this equals a velocity of over 15 ft/sec. This would rip the tissue off of nearly any coral directly in it's path within close proximity. Most powerheads are similar with tremendous velocities at their output. The gemini powerheads are about the worst with 950 gph shooting out of about a 3/8" outlet at velocities exceeding 30 ft/sec.

My general rule of thumb is to try to keep velocities in the 5 ft/sec range. This basically is 700 gph for a 1" pipe; 1,000 gph for 1 1/4"; 1,500 gph for 1 1/2" and 3,000 gph for 2" pipe.

I also use sea swirls in combination with static returns as I do think this helps to aleviate dead spots. Some swirls are pointing in basically the same direction and simply intersect static returns to make a more turbulent flow pattern.

I have also added a Reeftec PE-2 unit and currently have it on a wavemaker to give the corals a bit of a break from the heavy flow that it provides. The velocity on it is a bit strong for corals less than 12" away and for now I'm giving them a break using a redsea wavemaster pro. I may end up running it 24/7 and also may run it with my elightmaster program on x10 to give a slack tide to match the moon rise and set.

Oh well, IMO the key is to maximize flow & minimize velocity as you might notice from my signature line. Typically our tanks are filled with very fast direct currents that don't provide the large wide flow patterns that our corals really need. This is very difficult to provide as many have mentioned but we can start by upsizing the plumbing we use from 1/2" and 3/4" loctite fittings to 1" and 1 1/4" PVC fittings as a start. Even taking the nozzle screwed into your sea swirl to leave the regular elbow will help a bit. On my 1" sea swirls the elbow is actually 1 1/4" but reduced down to a 1" nozzle. Removing the nozzle reduces the velocity by about 20%. Every little bit counts.

FWIW, Nathan

 

[Anonymous]

ernie,

i don't doubt that the seaswirl is better. i am trying to get an answer as why 'a wavemaker' isn't better than 'no wavemaker'.

i think wavemakers would have to eliminate dead spots in some places. just the change in current would provide motion in areas that would otherwise have less.

most people point the powerheads at the glass or surface as opposed to a colony. that creates more than the "cone" you speak of.

if you had to choose between a wavemaker or just powerheads, which would you choose?

 

[Anonymous]

i think wavemakers would have to eliminate dead spots in some places. just the change in current would provide motion in areas that would otherwise have less.

I am not sure about this. The powerhead still pushes water to the same places with wavemaker or without one.

What are you thinking that I am missing?

RR

 

[Anonymous]

Righty,

i don't know if you are missing anything.

if a rock is sheltering a particular spot along the rock's side from a powerhead's output, wouldn't it be likely, that a powerhead that is in the "opposite" cycle directed against the original said powerhead, would direct flow at that previously "dead" spot when the first said powerhead turns off?

it's not that it pushes water to the same places with or without one, it's that it reaches new places when the currents change in the manner in which they work against each other. when a power head is left on constantly it makes a whirlpool of sorts. throw one that intermittantly pulses on and off and that whirl pool changes directions at times.

i don't know if you'll get that, a picture is worth a thousand words.

maybe i am missing something.

 

[SPC]

I understand what you are saying Podman, and agree 8O :lol: .

As to the Sea Swirls, I have the "Y" fitting on mine in order to minimize velocity as Nathan pointed out.
Steve

 

[D.W.L.]

I sold my Tsunami wavemaker years ago. Found it made no difference in my tank or corals health. I have always just ran opposing powerheads, creating random & turbulent currents.

On my new 225 sps tank, use closed loops. Currently running one on a small Iwaki and one on a Mak 4. Both will be on Mak 4,s soon. Experimenting with different size returns and how many. Seems to be best as Nathan said, with large diameter outputs and good volume. When running just the regular 3/4in on the Mak,s it is to much velocity.

 

[t-byrd]

would this be more on track then to whats natural?
im in the planning stages of setting up a 120g and what
i planned on doing for water flow is having the overflow at one far end
and the inlet for the closed loop on the same end.
and having the outlets for both on the opposite end through tubing so the water comes out near the bottom. not sure about
pumps, i was going to use 2 qiute ones for both but am beginning to think that wont cut it. what pumps would be recommended for this?
going to turn my current 55g into the refugium with mud and mangroves.

 

[mshur]

hm...i have been reading this thread from the begining,,i am new on reef,
but..if we minimize velocity,like nathan recomended...what to do with the curent..isnt curent important to keep sps...
i have 2 ssw ,one 3/4 with iwaki40rlt--returnt,and 1/2 for cloused loop powerd by mag7..i have pretty good curent..based on what nathat said,,i should remove nozzel part from my ss.and then i reduce curent...
hm...i dont
u guys more expirience then i am,can u explain to me please...
thankx,,,michael

 

[Anonymous]

hm...i have been reading this thread from the begining,,i am new on reef,
but..if we minimize velocity,like nathan recomended...what to do with the curent..isnt curent important to keep sps...
i have 2 ssw ,one 3/4 with iwaki40rlt--returnt,and 1/2 for cloused loop powerd by mag7..i have pretty good curent..based on what nathat said,,i should remove nozzel part from my ss.and then i reduce curent...
hm...i dont
u guys more expirience then i am,can u explain to me please...
thankx,,,michael

i think that would depend on the GPM you are pushing and the size of tank you have.

you may need the velocity to reach all corners of the tank. those are my opinions anyway.

 

[mshur]

i have 80g ...i push about 1100 gph...
plus i have cloused loop.with mag7

 

[Emperator]

i just set up a 40g prop tank and am pushing 2100gph. it is awesome!

 

[Anonymous]

Good points, Nathan. Hmmm, I just bought a Gemini powerhead... I figured I would set it up blowing across the front of the tank, and if I liked it getting another and alternating them on a wavemaker. So everything would only get deflected velocity. I wonder if I could split the nozzle on the Gemini to broaden the flow....

 

[Anonymous]

Here's a crazy thought: what if I broadened the nozzle to a short section of say, 1.5 inch and placed a deflector directly in front of the flow....?

 

[SalmonAlley]

Dan,
If you do make those mods to the Gemini you spoke of, please let us know how and how it has worked...I've got a Gemini myself and would be interested in reducing the velocity and intensity of it somewhat

SA

 

[Anonymous]

I'm on it! Any idea of the size of the exit nozzle on the gemini to save me a trip home?

 

[SalmonAlley]

Dan,
My bad...I didn't check the board frequently enough...hope I catch you before you leave...

O.D. is 3/4"
I.D. is 1/2 "

HTH!