Define Flow for SPS

[jtomasi]

Could someone give me specific GPH flow over SPS for it to be considered "High" and "Medium"? I always here people saying, "needs high flow", but have never seen numbers associated with it. People could have different opinions on what "High" actually is.

Also, although I doubt its linear and each pump is different, how much flow is reduced per inch of aquarium in general? For a hypothetical example, an MP10 is roughly 1500GPH at 1 inch, at 4 inchs, what would it be?

Thanks,

JP

 

[johntran216]

I just try to get at least 50x turnover for sps dominant tank. My tank is a 75g, so 75gx50 = 3750gph. I achieve this with 3 powerheads and a nano wavebox. I prefer using multiple smaller powerheads, instead of a single large one. I can point them in different areas and cause a more random flow that way.

 

[reefsandrotts]

hurricane conditions=happy sps

 

[KoleTang]

GPH is a factor when calculating how much flow you need/have. It means nothing to say "this much GPH" without saying your tank size.

That being said. About 50x turnover per hour is what you want. To calculate turnover add up your GPH of each pump then divide by the amount of gallons in your tank. (NOT your sump)

 

[spspirate]

For me its a visual thing. You want to see the polyps on all your SPS moving around in all sorts of directions. It may take some tweeking around with the power heads but just make sure everyone is getting some flow. Some may want more than others. Before you place a coral in your reef think about the species and how much light and flow it may need.

 

[jtomasi]

KoleTang, thank you for your reply and I understand what your saying, however, I specifically asked for distance for a reason. Again hypothetical, if I had a 500G tank and only 1 MP10, I could in theory put an Acro right in front of it and it would do fine. I understand that there is obviously a significant correlation between a multiple overturn of flow (in relation to tank size) and how well an SPS does, but that doesn't necessarily mean you couldn't keep them if you didn't meet that 50x or whatever requirement - which is why I refereed to GPH rate, not a multiple of tank size. and you could, in theory, measure GPH anywhere in the tank. I totally agree with what you said in that people should shoot for a multiple and that's what I do. I just wanted to know GPH becuase even assuming a tank has a 50x flow rate, the GPH in different areas of the tank aren't the same.

 

[chort55]

KoleTang, thank you for your reply and I understand what your saying, however, I specifically asked for distance for a reason. Again hypothetical, if I had a 500G tank and only 1 MP10, I could in theory put an Acro right in front of it and it would do fine. I understand that there is obviously a significant correlation between a multiple overturn of flow (in relation to tank size) and how well an SPS does, but that doesn't necessarily mean you couldn't keep them if you didn't meet that 50x or whatever requirement - which is why I refereed to GPH rate, not a multiple of tank size. and you could, in theory, measure GPH anywhere in the tank. I totally agree with what you said in that people should shoot for a multiple and that's what I do. I just wanted to know GPH becuase even assuming a tank has a 50x flow rate, the GPH in different areas of the tank aren't the same.

Dont try to overthink it... but if you'd still like to do that, you couldn't go with your example because 1. a mp10 wont work on a 500g tank unless.... 2. a 500g glass tank would not withstand the pressure if it was thin enough for a mp10 to properly function.

Random flow is what is important with sps, which is why the multiple powerheads and varied random flow is important. If you put most acros 1" from a 1500gph powerhead that powerhead will rip the flesh off said acro.


I had over 11,000 gph in my 180 (random timers made it anywhere from 2100-11000 at any given moment), sps loved it... sometimes flow would be lower sometimes ultrahigh, and even with a single powerhead constantly on flow in a specific location of the tank changes as the propeller spins around pushing water out in different directions, may not be extremely different, but still not the same 100% of the day ;)

 

[jtomasi]

I have a little less at 41/1 and want to make sure the SPS I am getting will have enough flow.

 

[jtomasi]

haha, bad example given the glass thickness but you get the point given what you said about the sps that close to a powerhead. lets say an MP60 (I dont know the exact GPH but I doubt it is 25,000GPH)

 

[chort55]

Stick your hand in the tank if the flow feels stronger then it is probably ok lol

As someone mentioned before, you want polyp movement w/ sps. It doesn't have to be whipping around so much your amazed they don't fall off, but good movement will be appreciated ;)

BTW, you may be able to find "flow @ x"" on the companies websites, ive never looked for it because I don't really care what it is as long as things are happy I am happy.

 

[johntran216]

Flow isn't jst movement for the corals. Flow helps keep detritus, food, and other junk from falling straight to the bottom and building up there, which keeps ur tank cleaner. Softies and zoas don't need that super clean system, nor do they care for high flow, that's why u can run less flow in their tanks. Something i've learned is that u want to look at the big picture in this hobby. One powerhead will definitely give u dead spots to worry about.

 

[jtomasi]

Thanks for the reply. I am clearly trying to quantify something that doesn't have an exact answer.

 

[mcarroll]

I just wanted to know GPH becuase even assuming a tank has a 50x flow rate, the GPH in different areas of the tank aren't the same.

I think you're trying to "back into" understanding flow from a strange perspective. Can't say right or wrong, but you're not going to find people thinking in those terms.

GPH is all but useless as a measurement or guide - you would need to know a much more complete description of the pump's flow (velocity, turbulence, reproccessing, etc) that you're interested in, as well as an accurate picture of the pump's operating environment. (GPH is barely useful in rating pump performance under "lab conditions".)

In reality characteristics of flow depend totally on context, so "summaries" like tank turnover are actually much more useful when you're still talking hypothetically.

Also, there's a lot of historical (i.e. bad) info still circulating in the net wisdom concerning flow. "Random" flow is not ideal. Neither is laminar. It wholely depends on the environment you're trying to replicate. FWIW, many polyps feed best under laminar flow conditions, and this is a predominant flow condition for many reefs. The flow generally changes by 180° in these reefs every 4-6 hours with the tide. Random currents arer still likely to be present to some degree and aid greatly in gas exchange and waste removal. I would say both flows should remain in our reef tanks, but laminar is a bit easier to create and is probably a bit more crucial in the short term. Without some randomized flow (at least a tide effect) you will end up with a detritus issue in the long term. It can be nicer to preempt this with more/better flow, but there are other ways too (i.e. gravel vacuuming, etc) as long as you are aware of it.

FWIW, most of our corals are from relatively greater depth where randomize flow (turbulence) is less of a factor. Corals known to be from surface waters are more likely (not guaranteed) to be from more turbulents zones. There are many exceptions and corals that thrive in both enviroments, so again the discussion must get down to talking about particulars instead of theory.

I hope this helps!

-Matt

P.S. Tunze posted a video a while back that goes a long way in showing or demonstrating the various aspects of flow and even compare a couple different kinds of powerheads, not just their own. Check it out:
[video=youtube;wPt735Fh-90]http://www.youtube.com/watch?v=wPt735Fh-90[/video]

 

[jtomasi]

At the very least people are getting some great info! Thanks for the reply, clearly I wasn't looking at ideal conditions for SPS the right way. I was really just trying to see from people if my 65g with roughly 2800 total GPH was enough for SPS and if not, could I just put it closer to the pump. I just didn't want opinions, I wanted hard numbers.

Mcarroll, it seems as if you are very well versed on flow and what is best for SPS. That said, given your statement on random and laminar flow, what would your advice be on where to place my pumps in my 65g Tall tank? I have a Reef Angel and can turn all but the return pump on/off whenever and how ever often I want.

Pumps:
Mag 7 Return
Hydor 750
2 Maxijet 1200 Pro (1200ph)

 

[jtomasi]

If placement is tough to answer, how would you turn them on/off during a 24 hour period? unfortuently I wont have my 2 MP40s for a few months so this is all I can do at the moment.

Thanks again - I really appreciate your detailed answer.

 

[mcarroll]

First, be prepared to experiment with whatever layout you try.

One easy, usually effective, setup to start with is with one pump on each side-glass, ideally situated above and/or in front of your rock line. (I.e so each pump has a clear shot across the tank.).

Run them as your tide simulation - one at a time, alternating back and forth at 4 to 6 hour intervals.

This placement and schedule minimizes the pumps working against one another and maximizes the momentum either pump can establish in the water.

Something like a Vortech or Tunze 6055 (which may be a less expensive option if you can control it with your Reef Angel) would be a fine addition to your tide effect to simultaneously add some randomized flow or better, a small wave. (And I think the Tunze pumps give better flow characteristics for rectangular tanks like yours, FWIW.)

One more good visual indicator for "enough" flow is to look at your sand. If it's of typical composition, your flow should occasionally be able to move some grains of sand. You can't be too strict about it as the idea is obviously not to move your sandbed, but the idea is that if your flow isn't able to do this, how is it going to flow any waste particles into the filter and keep them out of the sandbed?

-Matt

 

[jtomasi]

Thanks again Matt. So what you are saying is run the right pump for 4-6 hours, shut it off and run the left pump for 4-6 hours?

I actually decided to go bare bottom and will put in a DSP in my sump later (maybe). Right now I set it up so the Hydor 750 in as low on the tank as possible to push the detritus to one corner where I set up a maxijet to pull it off of the bottom glass and push it up towards my overflow . There is a small area that collects detritus but will be easy to clean once every couple of weeks when I do water changes. Per your suggestion, I will keep this setup but add another pump on the right side of the tank (opposite the current left pump)

Thanks again, Ill post pics when its all done.

 

[Zack]

Stick your hand in the tank if the flow feels stronger then it is probably ok lol

As someone mentioned before, you want polyp movement w/ sps. It doesn't have to be whipping around so much your amazed they don't fall off, but good movement will be appreciated ;)

BTW, you may be able to find "flow @ x"" on the companies websites, ive never looked for it because I don't really care what it is as long as things are happy I am happy.

Well said chort, leave.out the confusing stuff and keep it simple- if my corals are happy, I'm happy!

Sent from my VS950 4G using Forum Runner

 

[Chameleon]

2 mp40s coming....get ready to turn your tank into a washing machine :)

 

[dorky]

Wow! I learn something something new. I'm glad I found this thread. Thanks