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Old 01/07/2012, 06:50 AM   #276
Randy Holmes-Farley
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I'm not clear what you are asking, but if the question is whether wet skimming removes more organic matter than does siphoned water alone, then the answer is certainly yes unless you are sucking up piles of detritus and algae.

The more debatable point is whether a skimmer running dryer plus siphoned water changes is better or worse than wet skimming taking out the same amount of water.

My contention is that if wet skimmate is made simply by allowing less draining of the same skimmed water, then it cannot have less organic matter and probably has more. If wet skimmate is made relative to dry skimmate by other means than less drainage, then the answer is not clear. There is no measured data on these issues.

There is data on what is removed by skimming. Whether you think it may be removing something you want in the water depends on what you think you want removed and what you want to remain. Skimming does not select out soluble calcium, alkalinity, or magnesium for removal.


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Old 01/24/2012, 12:24 PM   #277
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I dont agree with this method. Its not going to hurt anything, but test your water. If your filtration (bio/mechanical) are good then you will never have to experiment with this. If every test I do reads "good" then why would I mess with this? Most beautiful tanks were not made by super wet skimming.


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Old 01/24/2012, 01:50 PM   #278
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Quote:
Originally Posted by greengeco82 View Post
I dont agree with this method. Its not going to hurt anything, but test your water. If your filtration (bio/mechanical) are good then you will never have to experiment with this. If every test I do reads "good" then why would I mess with this? Most beautiful tanks were not made by super wet skimming.
Since skimming removes organic matter primarily, do you test for that?

Copper will be mostly bound to organics which can be removed by skimming. Do you test for that?


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Old 02/07/2012, 05:37 PM   #279
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Its quite simple, If you have clean, broken in (Running long enough to produce skimmate) skimmer and compare it to the organic matter that is in your cup after one hour, and dry out the wet skimate you will roughly see that same amount of organics removed. but that's only part of the issue. Once a skimmer has been producing dry skimmate for over a week you will see a direct drop off of skimmate due to bubbles breaking on the way out of the skimmer,(this is due to inefficient bubble rise) Hence the organic build on the skimmer walls, to rectify this one would encompass a wet neck skimmer, to keep it clean, but it doses nothing for efficiency, the bubbles are still breaking. Not the third part of the issue, the type of skimmate and what it contains. this is where the is great diversity. The normal skimmer is only 12% efficient some are as low as 3% and the best under tank units scored 18%. Now Dont take these numbers and times them by the % they are lacking. As a bubble rises it needs to be in a state of uncontacted medium with other bubbles, not continually mixed and striped of there organics. it takes about 20 seconds for a bubble to become completely absorbent and unbreakable shell, it is at this stage organics rapidly are attracted to the bubble, the longer the bubble is in contact with the water, the more organics are removed, again this is amount of times the percent , the bubble starts to attract heavy metals in their last stages of full development, slowing the bubble further and collecting inorganic compounds.

So what does this have to do with wet vs dry skimmate? first it keeps your skimmer cleaner, which allows more organics removed, since I know only a few people clean there entire skimmer once a week, wet skimming is more beneficial they dry skimming. Adding of FSW over a longer period of time is better than dumping in 10-20% all at once.

Now if the skimmer is above 30 feet tall, then you would have ideal bubble rise and then you can see the difference of metals removed in the skimmate, a large amount research papers are done on this subject due to this is how your local sewer treatment plant works.


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Old 02/08/2012, 04:55 AM   #280
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Where did you get all that information? Some it of doesn't make sense to me. The metals part, for example.


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Old 02/08/2012, 11:46 PM   #281
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Randy, I came into the possession of a few white papers on the subject of Foam Fracturing in Sewage Treatment Plants, Advanced Treatment Operations, and a studly of the removal of metals during treatment.

Amongst the data was a break down of organics and non-organics, including many heavy metals both ferrous and Non-ferrous. This provided me with the rational that my little skimmer was removing metals in my fish tank. Well No, the more I researched, the more I found that Bubbles has definite laws of physics. I had a lab first test my skimmate, almost all organic compounds, I set up a 40' tube, and did a bubble rise test, and that led to a calculator based on Stokes Law. Next a ran my old tank water through the tube the foam extruded foam like a old comedy film. It poured out the top and blew in the wind, I captured most of the foam and had my friend re-analyze the skimmate, now not only did it have a incredible amount of organics, it had almost every metal conceivable. Basically I replicated the same information I found in the treatment of sewage. On another board, Reef Frontiers, he could have been the founder or just a Mod, I think it was Matt, but he was working on a Wet Head Skimmer, and had success in the rise in the amount of skimmate, I belive his first skimmer was 10-12 round and I think about 6-8' tall, he had his skimmate tested and there was trace amount of metals found, not nearly as much metals as mine, but that could have been from many factors, one his skimmer was still too short, the bubbles were forming yet they would not last out out of the chamber vary long, or my water, that never ever was skimmed and had more non-organics to begin with, My rocks might be leaching more non-organics, Then with more research I came along a paper the explained organic and non-organic adhesion in Bubble Rise/Foam Fracturing . So I began to build a real skimmer, the skimmer I made was 26 feet tall, but the rise chamber is only 18' ( my wife wont let me dig out the foundation of our house, nor let the skimmer penetrate the roof) It is powered by the same air stones that was used in the moderator of Reef Frontiers. (he Donated them to the cause) I use a CO2 compressor for soda, it is food grade and is oil-less, I tried others, non had the power to push almost 20' of water. But all of this came with a price, the powerful dump of the skimmer into my tank unleashed the seams, and we sprang a major leak, losing the entire contents, So on to build a better BIGGER tank, we are through with he tank, the skimmer up-grade, Minor mod to the design so my ceilings dont collapse again when there is a malfunction. (yes Im still Married) We have had the water and some fish in the tank for about a year running without any filtration, once I find a controller I will reconnect the skimmer, and test the skimmate from the first hook up and then months latter to see the removal of metals still continues.

I still have most of the papers somewhere I used and can copy them if you like. I think I have the calculator I designed also, it was spot on, most people found it a bit confusing, but my mind is not linear and nor was the calculator.


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Old 02/09/2012, 04:55 AM   #282
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Thanks.

I'm not sure which metals you are referring to, but many of them, like copper, are nearly completely bound by organics in normal seawater. Consequently, they would not be skimmed differently than "organics", but they are removed in skimmate.

Also, free dissolved metals not bound to organics won't be attracted to an air/water interface and won't be skimmed at all.


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Old 02/09/2012, 06:17 AM   #283
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Most metals only bind in the last phase of bubble rise/formation, typical skimmers (under tank/hang on back) actually strip the bubble before its fully formed. The result is only the removal of oils and mostly organics. My friend that did the test was the lab tester for a large sewage treatment plant.


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Old 02/09/2012, 10:28 AM   #284
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Quote:
Originally Posted by crazzyreefer View Post
Most metals only bind in the last phase of bubble rise/formation, typical skimmers (under tank/hang on back) actually strip the bubble before its fully formed. The result is only the removal of oils and mostly organics. My friend that did the test was the lab tester for a large sewage treatment plant.
That's the part I do not believe, at least for seawater. Metals bound to organics will bind with other organics, and those not bound to organics will not be skimmed at all.


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Old 02/10/2012, 09:39 AM   #285
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Randy, if you run the residue from the neck of a off the shelf production skimmer through a GCMS you will find a high concentration of non-organics, but if you do the same test with the skimmate you will find very little. Over and over the test we did came out with the same results, yet when I test the skimmate from my foam, all the organics and non-organics are present. The foam doesn't dissipate, and this has to do with travel time.

Now I never tested "wet skimmate" it might reveal that instead of binding to the neck it will be washed out with the skimmate, But my instinct tells me that the neck is coated with organics, much like a fully formed bubble and is attracting them/catching them. This is an important factor to define, because if this is true then wet skimming is not removing the non-organics, yet the flawed design of a skimmer is.


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Old 02/10/2012, 11:28 AM   #286
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I'm not sure what you mean. What nonorganics are you detecting by GCMS?

I agree that there are lots of nonorganics in skimmate, things like calcium carbonate, but they are generally not detectable by GCMS, and are present in skimmate. Ken Feldman showed that in this article:

http://www.advancedaquarist.com/2010/2/aafeature


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Old 02/10/2012, 12:58 PM   #287
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Quote:
Originally Posted by Randy Holmes-Farley View Post
I'm not sure what you mean. What nonorganics are you detecting by GCMS?

I agree that there are lots of nonorganics in skimmate, things like calcium carbonate, but they are generally not detectable by GCMS, and are present in skimmate. Ken Feldman showed that in this article:

http://www.advancedaquarist.com/2010/2/aafeature
Thanks Randy for another good read

Did I read right "Cl" as in chlorine ?? Deadly ??


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Old 02/10/2012, 12:59 PM   #288
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I am using the wet skimmate method to perform daily 5gl water changes within a 45 minute period on a 120gl system.
Will this do anything do alleviate sulfate buildup from dosing Epsom Salts?
Is there a practical way for the layman to test for sulfur/sulfate content in saltwater?


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Old 02/10/2012, 01:34 PM   #289
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Thanks Randy for another good read

Did I read right "Cl" as in chlorine ?? Deadly ??
It is listed as chlorine atom, but just for identification. If it were present in the chlorine (Cl2) form, it would be a big problem. But as the chloride (Cl-) form, it is the single most common thing in seawater other than water.


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Old 02/13/2012, 09:54 AM   #290
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Quote:
Originally Posted by Randy Holmes-Farley View Post
It is listed as chlorine atom, but just for identification. If it were present in the chlorine (Cl2) form, it would be a big problem. But as the chloride (Cl-) form, it is the single most common thing in seawater other than water.
Ahhhhh much better. Thanks again.


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Old 02/13/2012, 10:10 AM   #291
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Randy, the H&S skimmer is a ok production model, but the bubble rise is about 8", at this contact time, the removal is completely different. If a person took his Honda around a test track and told me a cars top speed is 125 mph, but we know that's not the truth, its 125mph for that Honda.The results published For most people will be more or less accurate, but this isn't the same thing as the skimmer I built. The non agitated contact time is the most important. Ill dig up my results in storage.


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Old 03/29/2012, 05:40 PM   #292
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Thumbs up

This thread may be about water changes via wet skimming and it seems some folks interpret that to mean periodic wet skimming for periodic water changes, but it needn't be restricted to periodic water changes. Just like the fellows in the beginning of the thread found, skimming a little wet continuously takes care of skimming and water changes for you automatically. I've been skimming ~0.75% of my system volume daily as my sole water change for a while now and both my tank and I are loving it! (That roughly equates to a 5% weekly or 20% monthly water change.)

Pros and cons as I see them:

Pros:
- Skimming a bit wet reduces my skimmer maintenance
- My water-change workload is reduced to refilling a reservoir of saltwater--the system deals with removing the old and replacing with new for me.
- Lower stress on the tank inhabitants (no drastic changes to water parameters)
- Easier maintenance means it is more likely to get done.
- Waste-water for changes has more gunk than taking it from the display/sump.
- Almost house-sitter proof
I do believe wetter skimming removes more DOC than dry skimming. (To paraphrase Randy, less water draining from the foam = less organics draining with it.) Whether that's 0.0001% more or 50% more, and what the cost/benefit is regarding producing the make-up water are both unanswered questions. However, if I am going to be removing roughly the same amount of water anyway doing water changes, the cost is close enough to the same whether I remove it with a skimmer or some other means. That leaves the question of just how much more effective is wet skimming at removing DOC. That's another fine question for another thread, but to me it is enough to know that the answer is definitely "more".

Cons:
- Continuous water changes use a bit more water on an annualized basis for the same effect. See Randy's article in the October 2005 issue of Reefkeeping for more on that.
- If you don't have access to drain the skimmate and have to manually do so, reduced workload may not be as big of a factor for you.
- May be more capital intensive and has more parts to potentially fail than manual water changes and manual skimmer-cup cleaning.
Feel free to check my math (not my strong suit), but for folks considering combining wet skimming with a continuous water change system, here are some rough equivalents:
10.00% monthly = 2.40% weekly = 0.35% daily
15.00% monthly = 3.68% weekly = 0.53% daily
20.00% monthly = 5.02% weekly = 0.73% daily
25.00% monthly = 6.42% weekly = 0.94% daily
30.00% monthly = 7.90% weekly = 1.17% daily



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Old 04/25/2012, 02:00 PM   #293
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What color skimmate is everybody getting??? Just did this for the first time and my skimmate is not quite coming out that tea color everybody is saying they are getting... attached is a picture of my skimmate next to a bottle of regular water... you'll see that it's just slightly cloudy but there is almost no color... that was from 4 hours of wet skimming... how long does it take you guys to get about 5 gallons of skimmate??


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Old 06/05/2012, 03:57 PM   #294
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I am curious about the colors of skim ate as well. How are people making these big collection cups? I have a 5g bucket with a screw on lid. Also, it seems like vacuuming sand would be more productive.


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Old 08/09/2012, 06:41 PM   #295
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I have been using this wet-skimming water changes technique and I can attest that it works and saves me a lot on buying salt. My skimmer cup drains through a hose to the side of my house so the cup never overflows. Every 3 days or so, I perform this technique modified to my liking. First I clean my skimmer neck, then I check my salinity. If the sg is 1.025 I add saltwater to my sump to raise it an inch. If the sg is 1.026 I add ro/di water to raise it an inch. My skimmer will skim really wet until the sump level goes back to normal. At this time I also add vodka to the tank. I believe that during this wet skimming period the skimmer skims out additional bacteria that helps reduce nitrates and phosphates on top of the organics. This technique plus vacuuming the sump for mulm and cleaning the refugium/chaeto weekly helps keep my water clean and saves me a ton on buying reef crystals salt. Before I was changing 100 gallons of water per week but I deemed it unnecessary. I am glad I ran into this thread.


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Old 08/09/2012, 07:44 PM   #296
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thanks a lot for these pictures

Quote:
Originally Posted by mobert View Post
when the skimmer sucks fluid instead of air, it stops making bubbles and stops working. I put it below the standpipe as this is a better scenario than skimmer cup overflowing into the sump.

Here are a couple of quick pictures.

Another overall shot showing the vent:


The skimmer cup with the intake for my two venturi pumps going in the lid on the left. The black tape is so I know how far in the cup to push the tubes. the center is the stand pipe that goes to the sump and to the right of it is the 1/4" drain to the collection container that then goes to house sewage. I have to put a pipe cleaner in the 1/4" drain every so often as it can clog up:



Here is a top view of my collection container with the standpipe drain to sump next to it:


Here is a look at the collection container. See how clean the 1/4" polyethelene line to house sewage is? It has never been cleaned in the years it has been in use:


Hope this helps.




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Old 08/11/2012, 07:57 AM   #297
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Interesting, hadn't thought of trying this. Definitely going to try it. Makes good sense.


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Old 08/23/2012, 10:05 AM   #298
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I'm looking at this idea. What are the best methods?

I'm thinking of over filling my sump and putting a bucket on my skimmer cup.
How fast do you add the water to the sump? It appears to me that we would want to add the water slowly, like with a aqua lifter pump. This way the skimmer has time to make new skimate.


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Old 11/02/2012, 01:05 AM   #299
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How can this be adapted to a RSM 250? My skimmer was (still is, sometimes) overflowing, as it's fairly new, and sometimes I just turn the skimmer off and "syphon out" the collection cup to remove the excess of water when I don't really want to perform a full cleaning. It's not a huge amount of water this way (tea coloured, always), but if I let the skimmer on, it can be used to collect more water as explained in the method.
But how can I replace the water, if I don't have an auto method to refill it with salt water? Does it need to be done as fast as it seems (sorry if I misunderstood it)? Can I just collect the amount of water I want (say, 5%) then just use regular water premixed as in a regular water change? I think so, as the main reason of this method is to get the "filtered" water out of the tank right off the skimmer as it removes the junk, instead of just using a syphon.


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Old 12/11/2012, 11:31 AM   #300
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Is one skimmer better another?


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