overskimming ha!!

<a href=showthread.php?s=&postid=7879934#post7879934 target=_blank>Originally posted</a> by Gary Majchrzak


Corals NEED less light in a lower nutrient environment?
Did you word this correctly, Rich?
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Yes. It is worded correctly. Theres a reason why many people had to shorten their photoperiod whne they went barebottom. Some people need to run their halides 12 hours a day. Those with lower nutrients burn everything out doing that.
 
<a href=showthread.php?s=&postid=7880920#post7880920 target=_blank>Originally posted</a> by RichConley
Yes. It is worded correctly. Theres a reason why many people had to shorten their photoperiod whne they went barebottom. Some people need to run their halides 12 hours a day. Those with lower nutrients burn everything out doing that.
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isnt that like saying more time in light will make light penetrate deeper??

B
 
<a href=showthread.php?s=&postid=7878554#post7878554 target=_blank>Originally posted</a> by RichConley
Gary, a while back someone did some tests on aquarium water using DI water (or ozonized salt, something very clean basically) and some aquarium water that was visibly yellowed, and found that at typical aquarium depths, there was little to no difference in lighting intensity. The real difference comes in the fact that the corals NEED less light in a lower nutrient environment.

I'm gonna try to find the tests.
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I'm still waiting for you to post a link and/or cite your refernces on this one, Rich.
 
<a href=showthread.php?s=&postid=7880802#post7880802 target=_blank>Originally posted</a> by Gary Majchrzak
With swirling there is lateral as well as horizontal movement of the water/air mixture. (Water/air spins around inside the skimmer as opposed to simply passing vertically through the length of the skimmer.)
The swirling motion results in a greater distance that water being processed by the skimmer must travel. A greater distance to travel equals more contact time.
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For a given volume, if the rate of the water going in/out the skimmer stays the same then the vertical component of the water motion will stay the same. Meaning, regardless of swirling or not the water/air mixture will travel up and back down in the same amount of time. The horizontal component of the velocity of an air/water mixture traveling in the same direction adds nothing to the contact time. If it did then the rate in/out would change.
 
<a href=showthread.php?s=&postid=7880907#post7880907 target=_blank>Originally posted</a> by RichConley
No it doesnt.

THe bubbles just travel faster. They still rise at the same rate.
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Bubbles DO travel faster if swirling. That's the whole point. More distance to travel results in a greater contact time.
 
<a href=showthread.php?s=&postid=7880910#post7880910 target=_blank>Originally posted</a> by LFS_worker
Think of the time that any given bubble is in contact with any drop(s) of water.. my ASM has a contact time of about 2 seconds (guessing) the aerofoamer is somewhere around 10 senconds some go even longer if the proteins are attracted to air then just about the time that one bubble gets to the surface of the asm it pops and releases some of that organic polutant back into the water column. the foamer is a much much better skimmer.. hands down no contest .
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Not really talking about nw vs. beckett, just what the 'swirling' does on your aerofoamer vs not 'swirling' on your aerofoamer. If you take that 45 elbow off the aerofoamer, I think the contact time is the same because the rate in/out stays the same, so the vertical component of the air/water mixture stays the same also.
 
Moving on!
<a href=showthread.php?s=&postid=7876458#post7876458 target=_blank>Originally posted</a> by LFS_worker
I am actually planning to fead very little for now... Im more concerned about the xenia and they seem to be pulsing alot more sence the addition of the XL skimmer.


...as of 72 hrs into the test run all is going fantastic all corals look well the xenia are pulsing great, I must admit the 72 hr mark is kinda off a little bit ... it took me about 2 hrs to get the skimmer level correct.
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72 hours is very premature to rush to judgement, but isn't it interesting to hear that your (high organic loving) Xenia seem to be doing especially good?

(For those reading this thread and unaware of it, Brian is in my local reef club and I consider him a very competant reefkeeper. He really knows his stuff.)
 
<a href=showthread.php?s=&postid=7880982#post7880982 target=_blank>Originally posted</a> by Gary Majchrzak
Bubbles DO travel faster if swirling. That's the whole point. More distance to travel results in a greater contact time.
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Yes, they will have a greater speed and will travel a greater more (practically I don't think this will be the case though). But you have to look at the velocity and split it up into its horizontal and vertical components. The vertical velocity stays the same so the contact time is the same.

Practically, I don't know of any becketts that have straight vertical motion, they have a little swirl to them anyway.
 
, I think the contact time is the same because the rate in/out stays the same, so the vertical component of the air/water mixture stays the same also.
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yeah, the water flows through at the same rate, and you inject air at the same rate, but the air lingers longer in the body. swirling will make the bubbles linger in the body longer than not swirling. it's painfully obvious once you see an aerofoamer in action, especially when it fires up. but i like it more for the fact that it's the best way i've seen to fight turbulance. so that rather than having the body fully of eddies, upwelling and downwelling, where some bubbles rise and some get drawn down and it's generally chaotic, with swirling they are all very orderly circling the body as they slowly rise. no bubbles are ever traveling downward, taking proteins with them. and before anyone says it, it's way better than a diffusor plate imo. diffusor plates are designed to spread the cloud of bubbles out so they can fill out a short fat body, not so much to fight turbulance.


and i think the point gary is making about the test being scientific or not should be boiled down to: no matter what the results of this test are, they won't mean anything and everyone should understand this so that it doesn't start yet another reefing myth. we have enough of those. bad data is worse than no data.




edit: if you don't bel;ieve me on the bubble dwell time, you can prove it to yourself. drop an airstone in a bucket. turn it on for 20 seconds. turn it off. time how long it takes to be clear of bubbles. now do the same thing, but swirl the water this time. it will be night and day.
 
<a href=showthread.php?s=&postid=7881068#post7881068 target=_blank>Originally posted</a> by Gary Majchrzak
Skimming Basics 101
Read it carefully:

http://www.reefkeeping.com/issues/2002-06/fm/feature/index.php

Feel free to cite any references you have to the contrary or let's agree to disagree and move on with the original topic of this thread.
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I'm not trying to get into a big or mean debate about this. I only bring it up because 3 people made the same statement during the course of this discussion.

I've read that article, its a good article and I actually posted a link to it today, but if his reasoning is the same as you stated he's wrong about the swirling. And he gives no explanation about why its better, just says it is.

I have no idea what Mr. Marini got his phd in but my references are calculus. There is a vertical velocity component to the motion of the water. For a given volume, at a specific in/out rate, the vertical velocity will stay the same, and in that context the contact time will stay the same.

I appreciate the discussion. Thanks.
 
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<a href=showthread.php?s=&postid=7881079#post7881079 target=_blank>Originally posted</a> by manderx
yeah, the water flows through at the same rate, and you inject air at the same rate, but the air lingers longer in the body. swirling will make the bubbles linger in the body longer than not swirling.
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Contact time, the time the water is exposed to the bubbles, wouldn't change even if the air 'lingers' longer in the body (which I don't think is true) because the water is exposed to bubbles for the same amount of time because the in/out rate is the same. If the water stayed longer in the same skimmer body then the output rate (gph) would have to change.

I'm not sure how to explain this better.
<a href=showthread.php?s=&postid=7881117#post7881117 target=_blank>Originally posted</a> by LFS_worker
paul just a couple of references for you that really helped me :)
http://en.wikipedia.org/wiki/Protein_skimmer
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Thanks Brian but I'm a little past that point :).

I'm sorry your discussion is got side-tracked. Goodluck with the experiment, I also like to overskim.
 
<a href=showthread.php?s=&postid=7881118#post7881118 target=_blank>Originally posted</a> by kimoyo
I've read that article, its a good article and I actually posted a link to it today, but if his reasoning is the same as you stated he's wrong about the swirling. And he gives no explanation about why its better, just says it is.

I have no idea what Mr. Marini got his phd in but my references are calculus. There is a vertical velocity component to the motion of the water. For a given volume, at a specific in/out rate, the vertical velocity will stay the same, and in that context the contact time will stay the same.

I appreciate the discussion this. Thanks.
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Paul- think of it from another angle of logic:
For a given volume at a specific in/out rate the vertical velocity stays the same, right?
So... if one were to add horizontal velocity to this equation how could it NOT increase contact time? The bubbles need to travel a greater distance (at a greater speed) because the in/out rate stays the same.
Distance to travel equals contact time.
This is why skimmers for larger systems are often taller.
 
<a href=showthread.php?s=&postid=7880982#post7880982 target=_blank>Originally posted</a> by Gary Majchrzak
Bubbles DO travel faster if swirling. That's the whole point. More distance to travel results in a greater contact time.
Click to expand...

to quote Kimoyo
"The horizontal component of the velocity of an air/water mixture traveling in the same direction adds nothing to the contact time. If it did then the rate in/out would change"

You're not changing contact time. You're increasing the amount of water theyre exposed to, maybe, but you're not increasing contact time.

When you introduce swirling, you cause bubbles to colide, and that causes them to combine, whihc is bad.
 
anyone If I email you a video of the skimmer working can you post it??

Im not offended in any means by the side tracking I believe that a deep understanding of skimmers workings and dynamics is essential.

Im reading word for word ... I dont want to miss a thing that could teach me all new stuff ... which this article already has! An Open-mind can be my most valuable learning tool. Ill never hear anything If I have preconceived notions.

Gary ... thanks your the best!
 
In a previous post it sounded as though the xeniid colony was actually doing better than before the skimmer was attached ... I want to rephrase that...

The xenia colony seems to be status quo ;) they dont appear to be better or worse for now.
 
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