Another DIY Skimmer Thread Question

[Alittlefishy]

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


I've seen the basic design several times, so I am assuming that this works pretty well. I want to know if my feeding/pump would work, or should I use something different. The tank I have is not drilled, so I have a HOB overflow rated at 300gph that I would use to feed the skimmer. The pump that I already have is a Resun 225NW from my Octo HOB. I would meshmod the pump for finer bubbles, but has been a good pump so far. I'm planning on this being an external skimmer with the effluent draining into a sump so that all my overflow water gets skimmed. I currently have a 55, but will have to wait on my large upgrade to the 125 in favor of a 75 with the 55 as the sump. Will this work??? Will this work well??? More flow from my overflow, or bigger pump needed? It seems like I should be close according to info from here. http://www.hawkfish.org/snailman/skimmer101.htm

[Alittlefishy]

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.

[OneDummHikk]

Originally Posted by Alittlefishy

I've been looking though the threads, and am really turned on by this recirculating skimmer:
[IMG]file:///C:/DOCUME%7E1/tilljo00/LOCALS%7E1/Temp/moz-screenshot.jpg[/IMG]

Eh, that image tag didn't work


Ok, have you seen my skimmer info thread?
http://www.thereeftank.com/forums/f2...fo-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]

Originally Posted by Alittlefishy

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....-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/s...?i=20702&c=505

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

[Alittlefishy]

Randy, thanks for that image fix, just saw how big it was...lol

So need a different pump...no prob
I think the guy used an OceanRunner 3700 or a (Gen-x4100) that pushes 900gph with the needle wheel. Running both of the QO2200's would be like 80 watts together. Since I may need to use a pump to feed the skimmer, I would like to only use one efficient NW pump to recirc.
Here is my info site.
http://www.randystacye.com/diy_needle_wheel_skimmer.htm
I clicked on the lakee link near the bottom of the page.
Since it's just a recirc pump, would there be any head pressure?

[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.

[Alittlefishy]

Just "skimmed" through your thread, and it is packed with a lot of good info.

I'm thinking that the Octo 3000 @ 750gph might be better suited as a recirc pump for this size skimmer and use one of the QO2200's as a feed pump if the overflow won't work. I would rather use the overflow if I can since my QO don't like to start with any head on them...I have them in an over-the-wall CLS and one will restart by itself, and the other will not. Might be different if it doesn't have to pull water over the wall.

[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.

[Alittlefishy]

Originally Posted by 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.

I've heard of this before and was wondering if it would work or not. I might have to try it. Worst case is the skimmer will skim the water too well due to too much contact time. Since I can flow approx 300 gph, I could throttle that back to about 250-260gph and that would give me just about 2x my system volume through my skimmer and keep the flow constant at the same time.
As far as the recirc pump goes, seems like the criteria revolve around bubble size, air injection capability, and watts drawn. that being said, the aforementioned Octo pump might be the best for the buck since my QO's don't have the nw and would need to be modded...then again, why buy what you can first destroy with a few good mods....I have a flow meter, but it's graduated in 5scfm units from 0-30. It would help me guess though. It's still snowing, so it'll have to wait till tom. I could actually try both the Resun225 from my Current skimmer and a modded QO just for fun.

[Alittlefishy]

When I build this thing, I will take a lot of pics and measurments if you want to use them in your thread...assuming this works of course...lol I did read one thing in particular in your thread that I wondered about. You were talking about skimmer break-in taking time to build up the slime coat and what not. Whenever I get a new skimmer, I run it for several hours in vinegar water (like 1 quart to 4 gallons) then rinse it with RO/DI and run it in a bucket of ASW @ 1.026 (same as my tank) with about 5mL of stress coat conditioner...I use aquatan by SERA for a few more hours, then put the skimmer on the tank. I don't really have a break in period after that.

[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.

[Alittlefishy]

I hope to actually start mine in early april after I get moved into my townhome. I wish I could start it now since I've found that my HOB skimmer is just too small for my 55. Even with weekly 20gal water changes, I still have diatoms in this year old tank.