What does water flow look like?

stimpy4242

stimpy4242

Member
So this might seem like an odd question, but could someone post videos of what they would consider:
Light
Moderate
Strong
water flows? Maybe show how much a coral is moving in the flow or something similar. I am trying to decide what my flows are really like. It seems like some soft corals required high flow, but it would seem like they would just blow right off their rocks...
 
gatorwpb

gatorwpb

Active Member
Originally Posted by stimpy4242
http:///forum/post/2803372
So this might seem like an odd question, but could someone post videos of what they would consider:
Light
Moderate
Strong
water flows? Maybe show how much a coral is moving in the flow or something similar. I am trying to decide what my flows are really like. It seems like some soft corals required high flow, but it would seem like they would just blow right off their rocks...
Doubt anyone would have all three in a video, but just calculate how much turnover you have. total up the flow from your return pump and any powerheads or close-loop systems you have running. Then divide that by the size of your display tank. But remove the volume of sand and live rock, to get your true water volume.
Approximate ranges:
Light: 5x-20x turnover
Moderate: 20x-40x
Strong: 40x-100x
As far as the coral is concerned, it matters whether you have concentrated direct flow (bad) or widespread indirect flow (good).
I have approximately 5700 gph in my 65g, which I figure to be over 100x turnover. But I have growing sps colonies and lots of rock. Plus one pwerhead is aimed behind the rocks.
 
stimpy4242

stimpy4242

Member
So corals shouldn't be waving in the flow? Maybe waving is bad, moving only in one direction because of the flow?
 
natclanwy

natclanwy

Active Member
Waving isn't bad,(unless it is an SPS coral
) laid over flat against the rock is bad. You should see some disturbance at the surface also, how much depends on where your powerheads are pointed.
Don't forget when you're totaling up your flow to subtract for headloss on your return pumps.
 
stimpy4242

stimpy4242

Member
I know I have plenty of flow in my tank i have a 3600 CL system and another 2800 for my return. And I have 125 DT and 55 sump...so I know I have the flow. Just doesn't seem like it sometimes thats all.
 
gatorwpb

gatorwpb

Active Member
Sounds like you have plenty of flow.
Just dont forget that there is head loss in the CL and the return pump. Likely because of the plumbing, more headloss in the CL than the return.
Waving is fine, its the direct flow that doesnt vary thats bad. If you have flow that crashes into things like walls or rocks or flow from other powerheads, it creates random turbulence that the corals love.
I have mostly sps in my tank and I have over 100x turnover.
With lots of rock, I figure I have somewhere around 50g of water in my 65g display. I have 2 Sureflow modded MJ1200s (2100 gph with large prop), a modded Tunze 6025 blowing behind the rocks (approx 1000 gph) and a Mag 7 return (500 gph). So with approx. 5700 gph, my sps polyps get whipped around. But because of how I have the powerheads aimed, they are constantly whipped in different directions because the flow is turbulent.
My polyp extension is huge and my sand stays white.
 
saltn00b

saltn00b

Active Member
from my upgrade thread:
i got mods for my maxi jets, they are sureflows
(i started with a set of 900s with the original supplied prop, but i have since added a pair of 1200's with the Dumas props. )
the before flow (one MJ900 working normally, ~200 GPH i think?)

replaced with the sureflow :)
MJ900 sureflow should be around ~1800-2000 GPH, the 1200 with Dumas is rated around ~2500 GPH )

more on the mods here:
https://forums.saltwaterfish.com/t/247342/saltn00bs-multi-phase-upgrade-diary/160
 
stimpy4242

stimpy4242

Member
THANK YOU GUYS so much for posting those videos. So would you say the flow in those tanks is high flow? That is exactly what I needed to see. I can achieve that without a problem in my tank, it just seems to blow my sand around.
And I was giving you calclations on gph AFTER my head loss from plumbing...I am such a dork that I figured it out for each fitting and elbow and such, but nice curving flex pipe has taken out a lot of the elbows and such.
 
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