Skimming Principles - Page 10

goby1 · 01/08/2006, 02:43 PM

Crazzy, how does a skimmer remove all trace elements?
G1

goby1 · 01/09/2006, 04:45 AM

I wonder if a skimmer with Escobal's parameters, except at one turnover every hour, as opposed to one every 12 hours... would corals die of starvation after a few years/months? Anyone have instances they remeber hearing about, with actual results of this? I'm talking about massive/overkill amounts of skimming. I'm just wondering about the merits of overskimming vs. underskimming. It would be good to test the extremes of skimming, for example. One of these extremes has already been tested, of course....

G1

jnarowe · 01/09/2006, 09:17 AM

I don't think there is any such thing as "over-skimming". The skimmer can only skim what impurities are presented by the tank. If you feed more, you can get more skimmate, etc. but if there are low impurities, you will get a small amount of skimmate. That's why skimmers tend to get a lot of gunk when first installed but it tapers off later on.

IMO much of the tank size rating for skimmers is just bull. Although there can be some size issue like putting a small HOB on my tank wouldn't have good net results, but skimming results are related to tank inhabitants and and maintainance just as much if not more than tank size.

tinygiants · 01/09/2006, 09:38 AM

Quote:

Originally posted by jnarowe

IMO much of the tank size rating for skimmers is just bull. Although there can be some size issue like putting a small HOB on my tank wouldn't have good net results, but skimming results are related to tank inhabitants and and maintainance just as much if not more than tank size.

I both agree and disagree with that statement. I believe that many of the skimmers on the market are not really capable of skimming the tank size they claim. Skimmer size really comes down to turnover rate. How much water do you have to skim in a given peroid of time.

For me, if I use the principals of Escobal, I need to skim at 2 GPM. For Jonathons tank, it is closer to 20 GPM. Now that you know the feed rate, pick a skimmer that will yield adequate operation with those conditions. Normal skimmers for the average hobbiest would not give very good dwell time for a 20 GPM feed.

Dale

jnarowe · 01/09/2006, 12:25 PM

Well, in my case we aren't really talking about "normal" anyway, but your statement leaves the door wide open when you state "IF I use the principals of Escobal". "If" is a big IF!

If I have a lot of live rock. If I have a lot of tank cleaners. If I have a bare bottom. If I have a refugium. If I have a remote DSB. If I have 1 fish per 50 gals. If I have a rigorous maintainance schedule. We can go on-and-on with the IFs...

My assumption is that skimming is just one part of the tank cleaning process,and that a well rounded approach to a captive habitat will far out-weigh the best skimmer that can be built. I don't mean this in any argumentative way either and your data and practical results will be very useful to anyone who wishes to keep a reef tank. Most importantly, it will help people who are planning on buying a ready-made skimmer because they will be able to look at the design and make a much more informed purchasing decision. For DIY types like you and me, we can build a skimmer and see how it goes. If we want more skimming, we can build another one or add another one.

What I don't see in any reference material is how we can judge whether we are skimming enough or "too much". What measurement can we take? None really other than observing our system and determining whether improvement is neccessary.

goby1 · 01/09/2006, 05:03 PM

I guess the test system might come from somebody who has a large tank and a nano, and for some reason used the big skimmer from the large tank (maybe shut it down for some reason), and put in on the nano. There is of course the argument that the long term health of corals is dictated to some degree by the presence of zooplankton, like rotifers or something. I really have no idea what the numbers might be. With zero plankton, corals might run into health problems after awhile. I guess that's not the point of this thread though. Good discussion though. These skimmer threads are really interesting to me. Lots of new points that I never thought of. Keep it up...
G1

jnarowe · 01/09/2006, 05:40 PM

And you bring up the most interesting and puzzling thing for me: Many of the very best looking reef systems, and particularly SPS systems, have extremely low nutrient levels. They are highly skimmed, refugium scrubbed, treated with UV, and have other filtration as well. You can barely see the water if at all.

This doesn't quite match what I have seen in the wild. In fact when I originally set out to start a captive reef, I really envisioned a bit more murky environment. It's not just eye candy to me. I am looking to create as natural of an eco-system as I can. I realize that's somehwhat of an impractical dream, but I think in many ways it can be and has been acheived by others.

BeanAnimal · 01/09/2006, 08:14 PM

jnarowe I think the thing we have to remember is that thre are a lot of differences between our captive environment and the real reef. Things that occur in nature may not be doable in our systems. The reality is that we may have to do things rather different to sustain life. This includes nutrients, lighting, wave motion etc. The only thing you can do is try, and track your results and weight them against your expectations or desires.

Bean

crazzyreefer · 01/09/2006, 09:38 PM

you can remove all trace elements if bubble dwell is over 120 seconds, this combined with a correct turn over will remove even trace metals.

goby1 · 01/09/2006, 09:56 PM

Are you saying that metallic ions in seawater will stick to the air/water interface?
G1

jnarowe · 01/09/2006, 09:58 PM

crazzyreefer -- What are you writing about? Removing trace metals? Maybe trace crack!

BeanAnimal · 01/09/2006, 10:15 PM

I dunno.. he has popped in here a few times and commented, but I can't ever quite follow what the post is saying or is in reference to. It may well be that the crazzyreefer is just living up to his name!

In all honesty I think he is trying to convery information regarding the title of this thread. A skimmer of sufficient height and correct turnover should remove everything that is removable, for lack of better words.

tinygiants · 01/09/2006, 10:26 PM

I can tell you my skimmer fell far short of the 120 second bubble. I can also tell you that my bubbles do not rise at 3 cm/s as was originally stated by Crazzyreefer. He based that report on the paper he linked to. When I read the paper, I got something like 30 cm/s from it. I questioned it, but was assured that his numbers were based on fact. So I worked on my skimmers bubbles. I questioned him in a earlier post about this, but it was never answered. I was just trying to understand how he interpreted that number. Unless it was a case of a misplaced decimal point ( 30.0 vs 3.00 cm/s).

The reality I have found, is even my microbubbles rise faster than that. I would love to have a skimmer full of microbubbles, but I have yet to see that quantity of them from any skimmer air source.

In any case, I have my skimmer and it is working. I may change the riser setup.

Dale

jnarowe · 01/09/2006, 10:30 PM

Great to hear Dale. I have seen large beckett skimmers completely filled with micro-bubbles, but they are running on huge pumps.

BeanAnimal · 01/09/2006, 10:32 PM

What riser changes need to be made and why?

jnarowe · 01/09/2006, 10:32 PM

check ouot the last few posts in this thread.

tinygiants · 01/09/2006, 10:46 PM

Nice looking skimmer.

I do not like how my skimmer is handling the foam export.

BeanAnimal · 01/09/2006, 10:52 PM

Doh... more details?

jnarowe · 01/09/2006, 10:52 PM

you know what the old coach would say, "Get a bigger cup!"

crazzyreefer · 01/11/2006, 12:21 PM

the organics creats surfactants on the extrior walls of the bubbles as they form, after 120 seconds the exterior walls have fully formed and increasingly collecting more organics and trace elements, Ill find the page that was linkd I believe to this thread or one of the other threads on this matter, it showed proof of what is being removed from our tanks, both in skimmate and in sludge from the riser tube, the riser tube had had larger percentage of heavy metals. a proper bubble would be less likly to burst and more likly to cary these metals into the skimmate instead of depositing them on the riser tube.

found the page...
http://reefkeeping.com/issues/2002-1...ture/index.php

As for buble rise rate this is where I found the info
this comes from the UCLA Paper on buble rise

Bubbles are ellipsoidal in shape, motion is irregular, and velocity is independent of
bubble diameter (approx. 28 - 30 cm/sec) for bubbles having radii up to 0.75 cm. For
larger bubbles their velocity tends to increase to 35 - 40 cm/sec, but they are not stable
and tend to subdivide into smaller bubbles.

Now we know we are having diffrent numbers comming in, one person reported 5 inches per second and I think your is 8 inches per second, these are way off, we will have to find away to explain the diffrences and then work togeather on a soulution.

jnarowe, I submitted your reply to the mods for review.

jnarowe · 01/11/2006, 12:32 PM

crazzyreefer What does that mean, you submitted my reply for the mods to review? What reply? What needed to be reviewed?

crazzyreefer · 01/11/2006, 04:02 PM

tiny, yea I lost a decimal some how the proper rise rate would be 28cm-30cm or 11.02-11.81 inches per second to reach the correct rise in static water is 118 feet worth of pipe, or a counter curent model to substanualy slow down the bubble rise

tinygiants · 01/11/2006, 08:03 PM

Well, I got some info from Spazz on his NW. I will crunch the numbers and see how my bubbles compare to his.

Dale

BeanAnimal · 01/11/2006, 09:04 PM

How is the skimmer working?

Are you using the recirc?

tinygiants · 01/11/2006, 09:50 PM

I am still not happy with my tunning. I either flood or get nothing. I am trying to find the sweet spot.

Right now I have the recirc off while I base line.

Dale

01/09/2006, 09:17 AM	#228
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	I don't think there is any such thing as "over-skimming". The skimmer can only skim what impurities are presented by the tank. If you feed more, you can get more skimmate, etc. but if there are low impurities, you will get a small amount of skimmate. That's why skimmers tend to get a lot of gunk when first installed but it tapers off later on. IMO much of the tank size rating for skimmers is just bull. Although there can be some size issue like putting a small HOB on my tank wouldn't have good net results, but skimming results are related to tank inhabitants and and maintainance just as much if not more than tank size. __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/09/2006, 12:25 PM	#230
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	Well, in my case we aren't really talking about "normal" anyway, but your statement leaves the door wide open when you state "IF I use the principals of Escobal". "If" is a big IF! If I have a lot of live rock. If I have a lot of tank cleaners. If I have a bare bottom. If I have a refugium. If I have a remote DSB. If I have 1 fish per 50 gals. If I have a rigorous maintainance schedule. We can go on-and-on with the IFs... My assumption is that skimming is just one part of the tank cleaning process,and that a well rounded approach to a captive habitat will far out-weigh the best skimmer that can be built. I don't mean this in any argumentative way either and your data and practical results will be very useful to anyone who wishes to keep a reef tank. Most importantly, it will help people who are planning on buying a ready-made skimmer because they will be able to look at the design and make a much more informed purchasing decision. For DIY types like you and me, we can build a skimmer and see how it goes. If we want more skimming, we can build another one or add another one. What I don't see in any reference material is how we can judge whether we are skimming enough or "too much". What measurement can we take? None really other than observing our system and determining whether improvement is neccessary. __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/09/2006, 05:40 PM	#232
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	And you bring up the most interesting and puzzling thing for me: Many of the very best looking reef systems, and particularly SPS systems, have extremely low nutrient levels. They are highly skimmed, refugium scrubbed, treated with UV, and have other filtration as well. You can barely see the water if at all. This doesn't quite match what I have seen in the wild. In fact when I originally set out to start a captive reef, I really envisioned a bit more murky environment. It's not just eye candy to me. I am looking to create as natural of an eco-system as I can. I realize that's somehwhat of an impractical dream, but I think in many ways it can be and has been acheived by others. __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/09/2006, 09:38 PM	#234
crazzyreefer Registered Member Join Date: Apr 2004 Location: Benicia, Ca. Posts: 1,455	you can remove all trace elements if bubble dwell is over 120 seconds, this combined with a correct turn over will remove even trace metals. __________________ If I see one more Snail I hope its on my plate served as escargot !!!

01/09/2006, 09:58 PM	#236
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	crazzyreefer -- What are you writing about? Removing trace metals? Maybe trace crack! __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/08/2006, 02:43 PM	#226
goby1 Premium Member Join Date: Feb 2004 Location: san francisco Posts: 364	Crazzy, how does a skimmer remove all trace elements? G1

01/09/2006, 04:45 AM	#227
goby1 Premium Member Join Date: Feb 2004 Location: san francisco Posts: 364	I wonder if a skimmer with Escobal's parameters, except at one turnover every hour, as opposed to one every 12 hours... would corals die of starvation after a few years/months? Anyone have instances they remeber hearing about, with actual results of this? I'm talking about massive/overkill amounts of skimming. I'm just wondering about the merits of overskimming vs. underskimming. It would be good to test the extremes of skimming, for example. One of these extremes has already been tested, of course.... G1

01/09/2006, 05:03 PM	#231
goby1 Premium Member Join Date: Feb 2004 Location: san francisco Posts: 364	I guess the test system might come from somebody who has a large tank and a nano, and for some reason used the big skimmer from the large tank (maybe shut it down for some reason), and put in on the nano. There is of course the argument that the long term health of corals is dictated to some degree by the presence of zooplankton, like rotifers or something. I really have no idea what the numbers might be. With zero plankton, corals might run into health problems after awhile. I guess that's not the point of this thread though. Good discussion though. These skimmer threads are really interesting to me. Lots of new points that I never thought of. Keep it up... G1

01/09/2006, 08:14 PM	#233
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	jnarowe I think the thing we have to remember is that thre are a lot of differences between our captive environment and the real reef. Things that occur in nature may not be doable in our systems. The reality is that we may have to do things rather different to sustain life. This includes nutrients, lighting, wave motion etc. The only thing you can do is try, and track your results and weight them against your expectations or desires. Bean

01/09/2006, 09:56 PM	#235
goby1 Premium Member Join Date: Feb 2004 Location: san francisco Posts: 364	Are you saying that metallic ions in seawater will stick to the air/water interface? G1

01/09/2006, 10:15 PM	#237
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	I dunno.. he has popped in here a few times and commented, but I can't ever quite follow what the post is saying or is in reference to. It may well be that the crazzyreefer is just living up to his name! In all honesty I think he is trying to convery information regarding the title of this thread. A skimmer of sufficient height and correct turnover should remove everything that is removable, for lack of better words.

01/09/2006, 10:26 PM	#238
tinygiants Registered Member Join Date: Mar 2005 Posts: 492	I can tell you my skimmer fell far short of the 120 second bubble. I can also tell you that my bubbles do not rise at 3 cm/s as was originally stated by Crazzyreefer. He based that report on the paper he linked to. When I read the paper, I got something like 30 cm/s from it. I questioned it, but was assured that his numbers were based on fact. So I worked on my skimmers bubbles. I questioned him in a earlier post about this, but it was never answered. I was just trying to understand how he interpreted that number. Unless it was a case of a misplaced decimal point ( 30.0 vs 3.00 cm/s). The reality I have found, is even my microbubbles rise faster than that. I would love to have a skimmer full of microbubbles, but I have yet to see that quantity of them from any skimmer air source. In any case, I have my skimmer and it is working. I may change the riser setup. Dale

01/09/2006, 10:30 PM	#239
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	Great to hear Dale. I have seen large beckett skimmers completely filled with micro-bubbles, but they are running on huge pumps. __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/09/2006, 10:32 PM	#240
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	What riser changes need to be made and why?

01/09/2006, 10:32 PM	#241
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	check ouot the last few posts in this thread. __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/09/2006, 10:46 PM	#242
tinygiants Registered Member Join Date: Mar 2005 Posts: 492	Nice looking skimmer. I do not like how my skimmer is handling the foam export.

01/09/2006, 10:52 PM	#243
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	Doh... more details?

01/09/2006, 10:52 PM	#244
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	you know what the old coach would say, "Get a bigger cup!" __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/11/2006, 12:21 PM	#245
crazzyreefer Registered Member Join Date: Apr 2004 Location: Benicia, Ca. Posts: 1,455	the organics creats surfactants on the extrior walls of the bubbles as they form, after 120 seconds the exterior walls have fully formed and increasingly collecting more organics and trace elements, Ill find the page that was linkd I believe to this thread or one of the other threads on this matter, it showed proof of what is being removed from our tanks, both in skimmate and in sludge from the riser tube, the riser tube had had larger percentage of heavy metals. a proper bubble would be less likly to burst and more likly to cary these metals into the skimmate instead of depositing them on the riser tube. found the page... http://reefkeeping.com/issues/2002-1...ture/index.php As for buble rise rate this is where I found the info this comes from the UCLA Paper on buble rise Bubbles are ellipsoidal in shape, motion is irregular, and velocity is independent of bubble diameter (approx. 28 - 30 cm/sec) for bubbles having radii up to 0.75 cm. For larger bubbles their velocity tends to increase to 35 - 40 cm/sec, but they are not stable and tend to subdivide into smaller bubbles. Now we know we are having diffrent numbers comming in, one person reported 5 inches per second and I think your is 8 inches per second, these are way off, we will have to find away to explain the diffrences and then work togeather on a soulution. jnarowe, I submitted your reply to the mods for review. __________________ If I see one more Snail I hope its on my plate served as escargot !!!

01/11/2006, 12:32 PM	#246
jnarowe Registered Member Join Date: Feb 2005 Location: Poulsbo, WA Posts: 14,710	crazzyreefer What does that mean, you submitted my reply for the mods to review? What reply? What needed to be reviewed? __________________ Jonathan--Recovering Tankaholic. Current Tank Info: 70g fresh planted

01/11/2006, 04:02 PM	#247
crazzyreefer Registered Member Join Date: Apr 2004 Location: Benicia, Ca. Posts: 1,455	tiny, yea I lost a decimal some how the proper rise rate would be 28cm-30cm or 11.02-11.81 inches per second to reach the correct rise in static water is 118 feet worth of pipe, or a counter curent model to substanualy slow down the bubble rise __________________ If I see one more Snail I hope its on my plate served as escargot !!!

01/11/2006, 08:03 PM	#248
tinygiants Registered Member Join Date: Mar 2005 Posts: 492	Well, I got some info from Spazz on his NW. I will crunch the numbers and see how my bubbles compare to his. Dale

01/11/2006, 09:04 PM	#249
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	How is the skimmer working? Are you using the recirc?

01/11/2006, 09:50 PM	#250
tinygiants Registered Member Join Date: Mar 2005 Posts: 492	I am still not happy with my tunning. I either flood or get nothing. I am trying to find the sweet spot. Right now I have the recirc off while I base line. Dale