Tank flow questions

<a href=showthread.php?s=&postid=10508538#post10508538 target=_blank>Originally posted</a> by JetCat USA
i guess someone needs to pass that bit of information along to the Big Man upstairs, seams his oceans have very random alternating turbulent flow across his reefs. like i said your posts strike me as more trying your best to be confrontational then educational, if I'm wrong in my perception then i do apologies.
Click to expand...

You misunderstand what flow is like in the ocean.


Flow is strong, and unidirectional. Waves are present on the surface only. Where your corals are growing, the vast majority of flow comes from tides moving in and out.


Huge unidirectional flow, switching directions every 6 or so hours.
 
<a href=showthread.php?s=&postid=10508624#post10508624 target=_blank>Originally posted</a> by RichConley
Waves are present on the surface only.
Click to expand...
OK, then what is undertow?
 
<a href=showthread.php?s=&postid=10508669#post10508669 target=_blank>Originally posted</a> by RichConley
Strong unidirectional current.
Click to expand...
So undertow changes with the tides?
 
I grew up around the ocean, and this idea of tides/waves, Rich, makes total sense to me. Is this what wave makers do? They switch "current directions"? If so, do closed tanks need that? If so... why? Does it help with dead spots, mostly?
 
<a href=showthread.php?s=&postid=10508695#post10508695 target=_blank>Originally posted</a> by Somrschool
I grew up around the ocean, and this idea of tides/waves, Rich, makes total sense to me. Is this what wave makers do? They switch "current directions"? If so, do closed tanks need that? If so... why? Does it help with dead spots, mostly?
Click to expand...


The fast switching wavemakers DO help with moving/changing dead spots, which is definitely helpful, but IMO, you're generally better off with more flow than less alternating flow.

IE, IMO, 2 tunzes running at 3000gph each are better than two tunzes switching back and forth from 3000gph to 1000gph.


The problem with the fast switching wavemakers is that they never get the water moving, as soon as it starts to move, direction switches. Theres no momentum. With non switching powerheads, you get much more momentum, and much faster speeds. You get mass water movement.


If you're gonna switch directions, do it every couple of hours or so. It'll work just as well for dead spots (every 6 hours, the previous dead spot will move halfway across the tank, and thats enough to get the waste in suspension) and you'll have much higher in tank water velocity.
 
<a href=showthread.php?s=&postid=10508698#post10508698 target=_blank>Originally posted</a> by RichConley
Actually, yeah, it does.
Click to expand...
So I do not need to worry about undertow while swimming in the ocean when the tide is coming in? Or going out?
 
On my dad's beach, it doesn't matter what the tide is. The undertow comes and goes, unpredictably, but I'm not sure if it changes direction. :-)

How close are reefs to beaches? I'd think that undertow would be more constant 'cause these are like currents that are part of the topography of the bottom/land masses, aren't they? (Thinking they are mini-Gulf streams, sort of...)

Am I close?
 
So, anyways, for an 80 bow, what would you guys recommend for powerheads?

AND, does the bow help with flow? Like, are they easier than rectangular tanks with sharp corners?

BTW: that was a great article. I read similar information in a book that is recently published.
 
not alot of info from me on natural ocean currents at reef levels but i would like to input my setup in hopes it helps. I have a vortec at the end of a 4 foot tank. Leave it up almost full (3000gph) shooting across the tank. I have a unmodded MJ 1200 ( 300 gph) shooting behind the rock work to keep detrius from building there and our return from the sump is sent through a SWCD and interupts the vortec at one side and goes with it a bit on the other ( 5-550 gph after loss for head and SWCD). the effect / flow is great ... strong unidirectonal most of the time but every 9-10 secs when the interupt side of the return is on i get a nice random current .
 
<a href=showthread.php?s=&postid=10508820#post10508820 target=_blank>Originally posted</a> by Somrschool
So, anyways, for an 80 bow, what would you guys recommend for powerheads?

AND, does the bow help with flow? Like, are they easier than rectangular tanks with sharp corners?

BTW: that was a great article. I read similar information in a book that is recently published.
Click to expand...

I've got a 72bow, and run a pair of maxistreams. The bow helps a little, in that if you point the powerhead at the bow, not as much will go up/down, but it doesnt make a huge difference.
 
OK :::ducking::: does anyone worry about dead zones under their rock work? I read stuff about making internal pvc skeletons and then placing rock on/around it... and I SEE lots of tanks that seem to have a simple wall of rock on which all the gorgeous corals grow happily. How important is it to you guys to leave space behind the rock; and do any of you jack it up/thin it out with hidden pvc pipes?

What do you guys think about flow/aquascaping when starting a new bow 80? Any advice about rock placement, how much rock (I'm beginning to read a lot of "more isn't always better; sometimes it's just more" from experienced folks who have good success with corals only to find that their corals are fast outgrowing their tanks.

What do you think?
 
Its funny, I've gone from a 29g, to a 58, to a 72, and I think I've sold off rock each time.

I think Ive got somewhere around 40lbs. Nice open rockscape.


Do a search for "Rock pillars". Theres a thread with a ton of nice open aquascapes.
 
<a href=showthread.php?s=&postid=10508784#post10508784 target=_blank>Originally posted</a> by Somrschool
How close are reefs to beaches?
Click to expand...
I've seen reefs you can walk to at low tide and some that are miles offshore. The location of the reef would determine what type of flow it receives. The better question is what types of corals grow on these different type of reefs with different flow patterns (I really do not know).
 
That's what I was thinking, Jim.

Rich: the board won't let me search 'cause I'm not a Premium Member. Can you link that "Rock pillars" thread for me, pretty please?
 
<a href=showthread.php?s=&postid=10508940#post10508940 target=_blank>Originally posted</a> by jimwat
I've seen reefs you can walk to at low tide and some that are miles offshore. The location of the reef would determine what type of flow it receives. The better question is what types of corals grow on these different type of reefs with different flow patterns (I really do not know).
Click to expand...

Jim, the point is that wave movement is so miniscule compared to the total amount of water moving through an area. The current is much stronger than the waves.


I'm not a premium member either, but google is your friend

"rock pillars" site:reefcentral.com

http://www.reefcentral.com/forums/showthread.php?s=&threadid=746318
 
THANKS, Rich. VERY much appreciated.

Wow, do I feel dumb. When i go there, they are saying "look at this picture" only I can't see the picture... is there somewhere to click to see these pillars? :(

Never mind; I figured it out. Thanks. :rollface:
 
Last edited:
<a href=showthread.php?s=&postid=10509001#post10509001 target=_blank>Originally posted</a> by RichConley
Jim, the point is that wave movement is so miniscule compared to the total amount of water moving through an area.
Click to expand...
This depends a lot on where you are. Back when I used to surf, the point was to find a spot where the wave movement was not so miniscule and it was often the place with the biggest reefs.
 
You must log in or register to reply here.

Similar threads

C
Coral placement and water flow
Replies
5
Views
145
wvned
wvned
E
Wave maker recommendations?
Replies
12
Views
372
ExitTrauma
E
S
Flow questions
Replies
5
Views
289
Sermanley
S
H
Hydor Koralia Nano: Experience the Power of Natural Flow!
Replies
0
Views
79
hydor_italy
H
Guygettnby
To reseal or not to reseal 120g.
Replies
5
Views
251
griss
griss
Back
Top