[OneDummHikk]

I've been looking though the threads, and am really turned on by this recirculating skimmer:

Eh, that image tag didn't work

Ok, have you seen my skimmer info thread?
http://www.thereeftank.com/forums/f218/skimmer-thoughts-and-info-124568.html

Some ramblings, but a lot of good info in that thread. The site you posted is part of the basis for the above thread.

First, the pump determines everything with a skimmer design. The amount of air it draws tells you the size of the neck. The water it pumps (not counting the air) helps determine the size of the body. It is all tied to the pump.

So, to answer your question. Will that design work? Yes. I - too - have seen it many times. Its a pretty neat design with off-the-shelf parts. Will it work with your pump? Thats a totally different question.

Do you have a Kill-A-Watt and Air Meter? Or access to them? Knowing what the pump is pumping helps a lot in figuring out the neck size as the amount of air tells your neck size. I have a chart somewhere that came from RC. I just paused and added it to the end of the skimmer thread. The basic rule is ~65 lph of air for every square inch of neck. So how much air your pump pumps will tell you the neck size.

It may end up that you need a larger/smaller neck size for your pump.

Feeding water to it. That is covered in the thread also. Its a toss up but for you, you can do it the way you describe, just be careful with it and figure out how to keep the flow to the skimmer consistant. The flow from an overflow can be erratic and introduce air bubbles into the skimmer and that will make it wonky acting.

If you decide to build this, post a thread. I look forward to it. I am curious where to find that neck on the top of the picture though. I have some sheet PVC for a base for a new DIY project but haven't found a coned neck like that one yet.

 

[OneDummHikk]

I will also have a pair of Quiet One 2200's that I could diy a venturi for if I needed more flow, but I would have to do something with the impellers. Forgot to mention that my skimmer will only be about 30-36" of chamber so that I'll have some head out of the overflow box.

OK, can you edit that first post and make it a thumbnail to the image? I have a 23" monitor and even at full screen, that image makes me have a scrollbar. Sheesh that thing is a HUGE Image!

Now, you posted this while I was typing my last post and adding some posts to other threads, so here goes.

QO2200? 40 watts, 2200 gph with zero head. At 10% air, thats 220 lph which means you would need a neck with a size of ~ 3 sq inches of surface area. Thats about a 2" neck. A 2" ID pipe has a surface area of 3.14 sq inches (pi * r * r). If you used both of them on it recirculating, you would go to a 3" neck. A 3" neck would have ~7 sq inches of surface area which is a little larger than what you need but a little oversized is better than a little undersized.

Will they work? Yes they will. The above is based on 10% air draw and 0 head. I am trying to find a head loss chart on that pump.

 

[OneDummHikk]

Found it. That didn't take long:
http://storefront.addictiveaquatics.com/products/QUIET_ONE_2200_PUMP_581GPH-1792-171.html

At 1M (~3') of head pressure (A 36" body) its down to around 1500lph gph on a 2200 pump. At 10% air draw, and running two of them, you would be putting 300lph of air into the body. At 65 lph, thats a little under 5 sq inches of neck surface area which translates to a neck size of about 1 1/2" so I might have been wrong about the pumps working.

Ever get the feeling that skimmers get my interest

 

[OneDummHikk]

I uploaded that image to my Image Gallery. It is here:



Go to this page:
http://www.thereeftank.com/gallery/showimage.php?i=20702&c=505

Copy the BB image code, edit that first post, replace it with the BB code. That image is HUGE man

 

[OneDummHikk]

Now I remember where I had seen that cone before. I have that link saved but haven't looked at it in a while. Someone should let him know the "Mantled Monster" skimmer he has linked isn't there anymore. It got "dismantled". Sorry, thats Geoffs joke but that site doesn't exist anymore.

There isn't near as much head pressure on a CLS type pump (recirculating) as there is against normal head pressure. With that, the head pressure doesn't really matter. Something I missed the first time.

Personally, I would try it with a single pump, with a 2" neck. Direct feed from the drain. Simply put the 2" pipe in the reducer, no other fittings. See how it works. If the single pump works out, you add the coupings and stuff, and build it. If it doesn't work, and you decide on a different pump, you aren't out any fittings or anything.

As for feeding the skimmer, I have an idea (untested) on how to keep the flow to the skimmer consistent. Give me a little bit to draw a picture and I will post it.

 

[OneDummHikk]

The drain from the tank comes down the pipe. The red is a crudely drawn gate valve. Below the gate valve is the skimmer feed, directly fed. The T simply lets excess water drain into the sump. The basic idea is that if you have X amount of gph coming through the drain, then you feed 90% (or so) directly into the skimmer by controlling it with the gate valve. Since you will never feed it 100%, it should never have air at the gate valve and thus provide fairly consistent feed water to the skimmer.

 

[OneDummHikk]

The one thing with that direct feed scenario is that the entry of the water into the skimmer MUST be below the bubble level in the tank, preferably at the inlet to the recirc pump, but in an air bubble free zone to prevent air bubbles from back feeding into the drain pipe.

Thanks for the compliment on the thread, its a work in progress and I hope it gets better as time goes on.

As for the pump, I say that since you already have the pump, and it won't cost anything to try it out, try it and see how it does. If it works, great. If it doesn't, then you aren't really out anything since you would simply change the pump and possibly the neck size.

 

[OneDummHikk]

It all starts with testing

Yes, pics would be awesome. I have a 6" pipe that I am working on a new build up of a skimmer for a DIY thread. I have a different base in mind but the top will be almost identical to what you are going to use. Other than maybe the neck up part depending on what pump I use on it.

 

[OneDummHikk]

Skimmer isn't going to help with diatoms. Not unless there is something about them I haven't found out yet that a skimmer will cure.

I hope to have something started this week on a skimmer. I have the base plate cut out but trying to come up with a good design and parts for it. I already have most of them, just have to figure out how I am going to assemble them.

Instead of the rubber plate that is on the link you showed, I have some sheet PVC that I cut the base plate out of. I am hoping it will provide a base to mount/sit the pump on instead of it just hanging off the side of the skimmer.

 

[OneDummHikk]

What I can't find out, although I have been trying to find out, is whether the pump bodies are the same. If the pump bodies are the same then you could get the impeller, volute housing, and venturi for a needlewheel pump and convert a "normal" pump to the needlewheel.

When I look at this page:
http://www.premiumaquatics.com/Merc...n=PROD&Product_Code=MAG2400&Category_Code=MAG
My Mag18'es (I have two of them) both look identical to that picture, even though the picture is of a Mag24. When I go look at replace covers, mine looks nothing like the ones they list for a Mag18 because they show a cover for a Mag2. So no way to know, without having both pumps or ordering the pieces, whether you can convert an old style to a venturi/needlewheel pump although I wish I could find out and know for sure.

 

[OneDummHikk]

When all else fails, you email Premium Aquatics and ask them. Hopefully I will get an answer in the next day or two as to whether or not I can "retro fit" the two Mag18'es I have with the new impeller and venturi.

 

[OneDummHikk]

Randy, I wouldn't see why they wouldn't fit. Why would the manufacturer redo the entire pump when all they needed to do was modify the volute and add a proper impeller?

Because if it were as simple as changing the impeller and volute then I would expect to see a lot more info about simply swapping it over since so many people have Mag pumps lying around. The Mag needlewheels are not new products, they have been out for a while now. And with them being out that long, and nothing showing where people have converted, then it might be a safe assumption that they may not swap out. And if they were made not to be able to swap out, then Mag could sell more pumps instead of just a retro kit.

I just looked at the site you were referencing for the build. If you decide to go with decent pumps, you are going to spend as much on the DIY skimmer for something that is going to take up a ton of space as you would if you bought one of the modded NW200's from Marine Solutions (modded with the Sicce pump ) like the one I have... for me, it would be a no brainer, I would just buy the skimmer from Marine Solutions...but that's just me.

I always have to laugh when I read things like that. "Ton of space"? The skimmer he referenced won't take up any more room than the Chinese made MSX skimmers do and possibly less.

Whether people DIY is a choice they make. Some people do, some people don't. It isn't always a better option nor a worse option. I wonder how hard it would be to get an MSX skimmer with a taller body? A DIY skimmer is ALWAYS more flexible with deisgn changes.

As for the cost, if you use a pump you already have, then its below 50 dollars for a DIY skimmer. How is a 200+ skimmer cheaper than a 50 dollar skimmer?

 

[OneDummHikk]

I had an entire reply to this typed up and have changed my mind. It simply isn't worth it.

.5Amp is what? ~55 watts? You should compare that to an Eheim 1262 pump.

 

[OneDummHikk]

I knew the Eheim was a higher wattage pump. But it doesn't stop you from seeing people recommend it as a "great pump". But, there is more to it than just the wattage it uses. I am still researching/testing but I am not so convinced anymore that the Sicce's are the answer-all for skimmer pumps. Time will tell though. I hope it is and that I am wrong though.

With regards to the mag series pump though, I did get an email from Premium Aquatics today and the impeller/housing for the needlewheel isn't sold seperate. The only way to get it is to buy the pump. Guess it means that if the impeller breaks, you have to buy another pump. None of it made sense. Although he did include a link to a venturi they offer that will fit the mag series pumps:

http://www.premiumaquatics.com/Merc...en=PROD&Product_Code=KENT-TVEN7&Category_Code=

I won't get into a DIY-vs-buy type debate here, it isn't what the thread is about. If he wants to DIY, then he can. If he decides to buy, thats his choice. I will simply try to answer his questions and let him make his own decision.

 

[OneDummHikk]

And at the rate I get things built, I might actually get something built for myself by 2012

 

[OneDummHikk]

I am guessing that they are the same volute and housing. There is a skimmer thread on RC where he used a Mag7 needlewheel and I asked him about the needlewheel impeller and he says it simply swaps out (Hes a mag pump lover and has many of them from the thread). I may have to spend 30 dollars and find out though.

 

[OneDummHikk]

Interesting about the air and makes good sense. Will do some checking on it and edit the other thread to include the air being different on a recirc.

 

[OneDummHikk]

After giving it some more thought, I am not so sure it is. I wish I had an Air Meter (I don't) that I could test it with. It wouldn't be a hard test to do with the right setup. A 6' or 8' pipe, a cap for one end of it, two uniseals to hook a pump to it, a venturi and an air meter.

Cap the "bottom" of the pipe, stand it vertically. Uniseal as close to the bottom as possible - inlet to the pump. Install a second uniseal 18-24" above the first one. That would be the outlet of the pump.

Put just enough water to cover the pump oulet an inch or so. Run it, record the air readings, repeat 8-10 times.
Raise the water level in the pipe 12", repeat the test 10 times.
Keep raising the water level until you reach the limit of the pipe.

As long as the pump setup wasn't changed, only the water level in the pipe, how efficient the pump is, the venturi or anything else was, it wouldn't matter because the differences in the air pull would tell you how much impact it had on it.

My brain is telling me why its going to pull less air but it isn't the water pressure itself but rather what the pump has to do to overcome it in the venturi. Its almost 4am, my brain is half working. When I get it straight in my head, will try to post and explain it.

 

[OneDummHikk]

Adam, the difference the amount of water in the pipe makes is how hard it is on the pump to create the vacuum. Even though the pump has the same pressure on both sides (inlet and outlet), it has to create a difference in pressure in order to draw air. It is that ability/inability to create a difference in pressure.

Take a small powerhead (MJ1200) and put it 4" below the surface of a display tank. Put an air line in the inlet of the pump, it will pull in air. Slowly lower the pump and it will stop drawing air. The pressure is the same on both sides of the venturi since its in a closed type system yet it stops pulling air. Why? Even though the pump can move water under 10' of water pressure, it can't overcome that pressure to create the difference in pressure needed to pull in air.

It changes a little with a skimmer pump since the pump body is outside but the internals of the pump are still submersed. The difference is how far the vacuum has to pull air. If its in 10' of water, it has to overcome that 10' of water pressure to get air to the pump. When its out of water but still has the 10' of water pressure inside the pump, it only has to create a vaccuum.

As Jason said, the Reeflo Dart pump starts losing its ability to draw air at roughly 4' of head pressure so Reeflo says to use the Alita Air pump to get air into it. And that is at only 4' of pressure on a pretty stout pump. It can pump water against a lot more head pressure than that but can't pull air at that depth.

Jason, it may have an impact on Becketts but I don't know for sure. I do know MRC builds a skimmer that is 8' or so tall (commercial unit) and it runs Becketts. The beckett chamber is - typically - above the water level to help try to combat salt creep stopping up the air inlets. The issue may come after the air is in it and trying to get the air to go down the tube and into the skimmer and that will come with water speed more than the pressure. The faster the water moves, the better chance it has of getting it down the tube and into the body. Its the reverse of getting air bubbles in the drain. If you get air bubbles in the drain of a skimmer, the water is moving too fast, slow the water down, no air in the drain. The opposite is true as well. The faster the water, more air out the drain. If you think of the piping after the beckett as the "drain", then its a little easier to picture (to me anyway). The faster the water is moving, the better chance it has of "sucking" the air along with it. And that is where the pressure rated pump comes in.

Lots of tinkering I can do with it if I ever get where I can tinker again. Right now my back isn't allowing it

 

[OneDummHikk]

Jason, its right. We are saying the same thing, just different ways/analogies of trying to say it.

Adam, you are right about vacuum vs low pressure. When I refer to a vacuum in a pump it is relative. If the pressure on the inlet side is X and the pressure on the outlet is X/2, then to me there is a vacuum on the outlet and will "aspirate". But, it is the difference in pressure that causes the air to be pulled in and the height of the skimmer isn't what causes the issue. The issue is caused by water pressure. And the water pressure that you need to be concerned with is whats in the pump itself and on each side of the venturi valve.

Go back to your Seaclone. It pulled air when the pump was at the surface of the aquarium. Yet when you moved the pump to the bottom of the aquarium, it stopped pulling air. The volume of water in the skimmer didn't change. What changed was the head pressure on the pump itself and the water it was pumping against. But its still a little different there because you weren't in a recirc setup, it was pumping and pulling air/water against the head pressure of the water column in the tank itself. And that brings up an interesting point about it. That's why skimmer manufacturers have a "preferred water depth" is so that the pump has the amount of head pressure needed to pull air properly. It has nothing to do with water level in the skimmer, which many people wrongly assume is the reason for the water depth criteria.

Assume that you have two identical skimmers. Same pumps, sizes, everything is identical. Both are recirculating skimmers. You set them up in two different scenarios. One is setup where the pump is in 12" of water. The other is setup where the pump is in 8' of water. The recirc pumps, not the skimmers. Which one will pull more air? The water volume in both skimmer bodies will be the same. The "head pressure" from the skimmer in both situations will be the same. The only difference would be how much water it has to pull air through to get it to the pump. The result might surprise you.