Zephrant said:If the design has truly been optimized, then the neck is long enough for the excess water in the foam to run back down into the skimmer, while the organics on the bubble surface overflow into the collection area.Scooterman said:Humm, I wonder about that, you'd think a longer neck would act like a channel for the skimmate./QUOTE]
Consider it this way- What ever skimmate enters the bottom of the neck, you want to exit the top, to be collected in the cup (the whole purpose of the skimmer of course). Anything that inhibits that foam from exiting the neck is bad.
Take it to extremes- Which works better, a skimmer with a 6" neck or one with a 24" neck? All else being equal, the extra 18" of neck just gives you that much more acrylic to clean. It also gives the foam that much more time to break down, and drip back in to the main chamber.
"Get the foam out!" should be the mantra of all skimmer designs.
Zeph
Go the other extreme (from a 24" neck) - no neck at all. Just let the water in the top of the skimmer overflow into the waste, and use an automatic system to add fresh saltwater. 100% efficient organic removal! (otherwise called a water change)
Skimming conversation
- Thread starter mojoreef
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DonW
R.I.P.
ldrhawke said:I have compared an airpump to a pinwheel pump. To get the same amount of air that a pinwheel pumps put into the skimmer you need a good size air pump that takes even more energy than the pinwheel to run. Using compressed air in any type of process is never cheap. Plus they are often noisier and require more maintenance than a magdrive pump. Let alone air stone replacement. If you can make bubbles without using a compressor, it is the way to go.
Could you give some examples of "pinwheel" pumps that are cheaper than an equal air pump?
Don
ldrhawke
John
DonW said:
I said use less power.......which is cheaper. I ran a Tetratec Deep Water Air Pump model DW24 and used wood fine bubble air stones. The model I used visually put out less that 1/4 of the amount of air bubbles that the Dolphin 900 did with a pinwheel impellor and pulled almost the same amperage. Air pump was using about 24 watts and the pump was only about 28 watts.
Compressing air to 2 to 4 psig to make fine bubbles and forcing it through an airstone isn't the most efficient way to create the air requirements of a skimmer.
ldrhawke
John
Don,
I looked at the photos in your gallery......boy that is some recirculation system. Are those two Dolphin 3000 pumps?
Are you training small Salmon to jump over the dams going back up stream...just kidding :badgrin: I can get over the amount of flow you must have in that tank. How is it working out? Do you throttle back the flow?
I looked at the photos in your gallery......boy that is some recirculation system. Are those two Dolphin 3000 pumps?
Are you training small Salmon to jump over the dams going back up stream...just kidding :badgrin: I can get over the amount of flow you must have in that tank. How is it working out? Do you throttle back the flow?
ldrhawke just to thro some numbers out thier. The deltec and the bubble king skimmers being tested bith max out at about 1 cfm. To accomplish that with air pump and stone it would cost you about 60 bucks for the pump and about 15 bucks for the stone. The pump runs @ 16 watts when run full bore. The stones these days are a lot different these days then the old wood ones. The stone I referenced puts out bubbles at 100 to 150 microns and are made from a heat bonded material and have a life span of 12 months and then can be cleaned by a simple muratic dip.
The bubbles are smaller, they are more passive, you can run the pump over a 100 feet away.
Just some food for thought
MIke
The bubbles are smaller, they are more passive, you can run the pump over a 100 feet away.
Just some food for thought
MIke
DonW
R.I.P.
ldrhawke said:
I started with a am3k and am2100 and Iwaki 30. I then converted the 2100 to a am3k. All run wide open, honestly it could probably handle a little more.
Don
ldrhawke
John
mojoreef said:
I don't think you are taking into account the airpump reduction in output vs backpressure. I know there are more efficient air stones, but they still have a major pressure drop and significantly reduce the airflow. A one psig pressure drop reduces the air flow to less than 1/2. 2 psig will virtually stop the flow in a small air 16 watt aquarium pump. The airflow rating you are giving is with no back pressure.
Wooden air stones are pretty efficient to start, but they plug easily. The amount of air coming out of my 24 watt air pump was a small fraction of a CFM and like I said not much more that 25% of the pinwheel pump. I have a difficult time believing an 18 watt air pump would be very effective, not that it wouldn't skim at all.
I'd love to see pictures of your airstone set up operating.
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DonW
R.I.P.
Think bigger. Average 1 cfm pump with a 9" fine stone = .9 cfm @ 2.5ft.
Don
Don
I went little silly on mine. I went with a 5 cfm pump at 5psi. Its a 100 feet away from the skimmer, It goes into 4 airstones that handle 1 cfm a peice and I have had to turn the air pump down by at least 30%. If I dont it blows the foam through the top (believe me it scared the crap out of me when I first turn i on
:evil: ) Wooden airstones only put out bubbles at 200 to 300 microns this stone does half the size, Also wooden stones break down as they age and rot. The pump I used is a linear pump from White water. I attached a 100 micron filter paper (shop vac lol) to the intake so the ony thing to get through is less then that which will pass through the stone.
Right now I have the water mixing chamber full of water and then a 5 foot column of shaving cream (the kind you can sculp faces in lol)
I willget off my butt tommorrow and try to take some pics for ya
Mike
SaltwaterTeen
Well-known member
Also, another way to tell efficency other than bubbles is the stench, if it smells bad then its probably doing a good job lol.
ldrhawke
John
mojoreef said:I went little silly on mine. I went with a 5 cfm pump at 5psi. Its a 100 feet away from the skimmer, It goes into 4 airstones that handle 1 cfm a peice and I have had to turn the air pump down by at least 30%. If I dont it blows the foam through the top (believe me it scared the crap out of me when I first turn i on
The pump I used is a linear pump from White water. I attached a 100 micron filter paper (shop vac lol) to the intake so the ony thing to get through is less then that which will pass through the stone.
Right now I have the water mixing chamber full of water and then a 5 foot column of shaving cream (the kind you can sculp faces in lol)
I willget off my butt tommorrow and try to take some pics for ya
Mike
Mike,
Over zealous is right.....if it is the model LT28 WHITEWATER, it is rated 130 watts at 2 psig. If your running at 5 psig, it will probably uses close to 250 watts at 5 psig compared to the 130 cfm at 2 psig. It only puts out just under 2 cfm at 5 psig.
It will use 5 to 10 times more for energy to operate compared to my SEDER 900 pinwheel. I considered the same approacj, but at 10 cents a kw, that equates to .60/ day; $18/month; or $216/ yr. For that operating cost it better make whip cream.
What ever happened to that 18 watt air pump? I don't think they will buy you package in europe.
Whitewater compressor curves http://www.reeffrontiers.com/forums/attachment.php?attachmentid=3500&stc=1
reefer
Well-known member
Marketing, Marketing, Marketing. It doesn't have to be better than the other guys its how you maket it to the consumer.coolcol said:
moonpod
FOWLR Janitor
reefer said:
You try making a skimmer that works as well as a Deltec. It ain't easy. The pumps are pricey. The body/neck ratios matter. They use very, very nice (overkill) fittings. Now granted, the materials cost is NOT anywhere near what they charge, but frankly the thing works really, really well, is made really, really well, and also of course you are also paying for the weak dollar relative to the euro. What you notice is that even the "DIY" guys that do work considered to be good quality and "cheap" charge a lot for a recirculating skimmer. It's just not that easy to make well. Conceptually any skimmer is "simple". Optimizing the design is not. I've used A LOT of skimmers and to date, the "tightest" best functining package I've used is the Deltec. Now the "cost" question....that's a relative issue, because what's "worth it" to one person is not to another.
Zephrant
Engineer
Think about it this way- A water pump (Eheim, etc) that moves water, and as a byproduct pulls air in though a venturi, is not going to be as efficient as a pump dedicated to pumping air. Even at the same measured air flow the water pump has to spend energy moving water.
While you can come up with cases where a specific cheap-o air pump takes more power than a Eheim, that should not be taken as conclusive proof that a well designed air pump can't do better for less power.
LDRHawke- I believe your reports that your air pump did not do as good as the Eheim, I just think that there should be an air pump out there that would do better.
Zeph
While you can come up with cases where a specific cheap-o air pump takes more power than a Eheim, that should not be taken as conclusive proof that a well designed air pump can't do better for less power.
LDRHawke- I believe your reports that your air pump did not do as good as the Eheim, I just think that there should be an air pump out there that would do better.
Zeph
DonW
R.I.P.
It woud take alot of sedras to power Mikes monster skimmer. The numbers above also assumes that the pump is running maxed out with the maximum psig. Not really possible with those stones unless they are plugged already. 100' away through a garden hose is pretty darn impressive.
Don
Don
ldrhawke
John
Zephrant said:Think about it this way- A water pump (Eheim, etc) that moves water, and as a byproduct pulls air in though a venturi, is not going to be as efficient as a pump dedicated to pumping air. Even at the same measured air flow the water pump has to spend energy moving water.
While you can come up with cases where a specific cheap-o air pump takes more power than a Eheim, that should not be taken as conclusive proof that a well designed air pump can't do better for less power.
LDRHawke- I believe your reports that your air pump did not do as good as the Eheim, I just think that there should be an air pump out there that would do better.
Zeph
Zeph,
Good points. If the whole question of skimmer effciency was based only the volume of air, I would agree with you. But, I believe other possible variables are not fully being taken into account on this topic. I believe that the energy imparted by the pinwheel in bubble and liquid contacting plays a significant role in over all skimmer efficiency.
For an air pump to efficiently make liquid gas contact it needs to produce fine bubbles and that requires pressure drop, even with the most efficient air stones. Pressure is energy and it consumes energy to obtain it.
In a pinwheel pump, which is far from new. They have been used in the food and pharmaceutical industry for ever. They are often called foam or emulsifying pumps. Infact, I believe the patents expired 20 years ago.
Pinwheel pumps impart the energy somewhat differently. It causes tremendous shear and mixing forces between the liquid and the gas. It also imparts high energy in flow, possibly electron charge, and gives rapid pressure change from the suction to the discharge side of the pump. I believe, but I have not run tests, so cannot prove it, that this dynamic pinwheel energy input between the waste organics and gas enhances the skimmer efficiency compared to simply releasing fine bubbles. Just my opinion :idea:
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ldrhawke
John
DonW said:
What Mike didn't tell you is why it is 100' away......the noise
.... :badgrin: I am sure Mikes skimmer is performing super. I considered doing the same thing. Even bought the air pump and stones. Word of advice to Mike...don't use that shaving cream your producing to shave with. Trust me, the lingering odor won't attract women
From the amount of foam I'm getting from my Sedra 900 while running tests I am sure a single pump would fully drive Mikes skimmer.
DonW
R.I.P.
ldrhawke said:
Are you talking about a 900gph sedra pump with a needle wheel and venturi?
Don
ldrhawke
John
DonW said:
YES....a 900gph sedra pump with a needle wheel and venturi.
ldrhawke
What made you change your mind??
On a side note here. I run a fairly large tank (1200 gallons total system) with some fairly large fish. I have run a etss downdraft 2500 for years, done multiple beckets and so on, none of them have come close to this one SO FAR. For me going out and buying a new skimmer for my size tank is not a drop in the park. I had Mr. Saxby pound me for hours at macna on a deltec, the unit for my tank was 5000 plus 1200 for the self cleaning head. The bubble king is even more, been down the Etss and beckette road. I just cant spend that kind of money on a skimmer. I built this skimmer for 400 bucks in acrylic and then changed my mind and went needle wheel, I put four OR 3700 on it and away it went, It was pretty good for foam but not as much as I expected. My etss was getting about twice as much. I puled the pumps and went back to the air drive and I am getting 4 to 5 times as much foam as I did with the Etss 2500. Show me a needle wheel that produces this much foam and skimmate for anywhere close to the price and I will starting wearing that shaving cream,
Take care folks
Mike
The pump I was refering to is the LT 11 which pushes 1 cfm @ 2 psi runing at 16 watts. Like I said for mine I went way over board on the size of mine. I might exchange it for the smaller unit like the LT 24 which is 3.5 cfm @ 2 psi @ 60 watts. I was tring to size the pump to match the output of the diffusors which was not the way to do it.
This could be a point but I am not sure. Protiens form on the surface of the bubble, do you think the air/water needs to be chopped in order for this to occur. or am I misunderstanding you??
Are you talking oxygen transfer?? or bubbles for making skimmer. For the skimmer the finer the bubbles the more pressure required to blow through the diffusor. But these diffusors will blow at .25psi.
Yep thier noisy, well this one is. I have a fish room so noise wasnt really an issue, I was more worried about moisture in the room clogging things up. But hey thats what garages are made for no?? LOL
LOL dont worry about that, oh du tank is not my fav.
What made you change your mind??
On a side note here. I run a fairly large tank (1200 gallons total system) with some fairly large fish. I have run a etss downdraft 2500 for years, done multiple beckets and so on, none of them have come close to this one SO FAR. For me going out and buying a new skimmer for my size tank is not a drop in the park. I had Mr. Saxby pound me for hours at macna on a deltec, the unit for my tank was 5000 plus 1200 for the self cleaning head. The bubble king is even more, been down the Etss and beckette road. I just cant spend that kind of money on a skimmer. I built this skimmer for 400 bucks in acrylic and then changed my mind and went needle wheel, I put four OR 3700 on it and away it went, It was pretty good for foam but not as much as I expected. My etss was getting about twice as much. I puled the pumps and went back to the air drive and I am getting 4 to 5 times as much foam as I did with the Etss 2500. Show me a needle wheel that produces this much foam and skimmate for anywhere close to the price and I will starting wearing that shaving cream,
Take care folks
Mike
