[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.

 

[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?

 

[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.

 

[Alittlefishy]

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....:rotflmao::rotflmao: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.

 

[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.

 

[Alittlefishy]

I've actually come up with a hybrid skimmer idea that is loosely based on the above referenced site's recirculating idea, but changed so that it will have a 24" reaction body instead of the 13" and a bubble plate like the MSX. I wonder if I will need the bubble plate since I am adding extra height to the reaction body?

I wanted to try the Resun (octo) pump since i had it on hand, and the QO2200 I have also. If they don't work as well as I would like, I will go with the sicce or the sedra pump.

Cost is a factor in my decision to DIY something, but only in the respect that an Off-The-Shelf Recirc skimmer for 200+ gallons starts at the $300 mark and goes up from there. My other reason is that I like to tinker with stuff. Although my tinkering depends on how much time I waste at work.:lol: I may have to skip the diy if I run out of time before the move. I'm planning on my new tank to be BB and I want to use something like Zeovit and the like to really make the corals pop. I really want to make sure that my skimmer is overkill either way I go.

The 55 tank will be used as the sump for a few weeks while I get settled in the new townhomes. After that, I will:
change to the 33L
upgrade the skimmer to the DIY or a store bought.
get new bulbs in my T-5 fixture
start working on an ATO so I can go on vacation

 

[Alittlefishy]

That looks easy enough, just wonder if it is enough of a needlewheel to chop the bubbles fine enough. If I chop up one of my QO pumps, I think I will cut half the impeller down and put enkamat in it's place, or make my own disk inpeller.

 

[Alittlefishy]

I agree and disagree all at the same time with three90s. First of all, the air flow drawn into the pump is dependent on the speed of the water flow across the venturi. Second, the speed of the water flow is dependent on head pressure differences between the input and output of the pump in question. In a CLS setup, the head pressure come from the water in the output pipe being pulled toward earth by gravity and slows the flow of the pump as that amount of water increases; i.e. more height, or larger diameter pipes. In this example, where a water tower is concerned, the "head pressure" is reletively equal on the input and output pipes. This means that the water speed through the pump is not affected very much, if at all, by the amount of water in the skimmer, or the height of the skimmer that the pump is attached to. However, the straw theory is almost right in that it takes more flow to empty the straw of water at deeper depths (overcome more head), but once the air is flowing through the venturi, it flows at the maximum flow of the diameter of the air tube. The reason for all this is that the speed of the water passing by the venturi is responsible for creating the vacuum that draws the air in and the amount of air in is directly dependent on the flow of water past the venture and the amount of vacuum it creates. Finally, my reason for thinking that the water flow through the pump is not affected is that the pump is not below the body of water, it is technically in the body of water.
Finally, again, the person blowing in the straw must overcome the weight of the water creating pressure in the straw, with a pump and venturi, the pressure is removed from the end of the straw and replaced by a vacuum created by the water rushing past it....whew. I'm 99% sure on all this, but I don't have a degree in fluid dynamics, but I do have a degree in avionics and as far as I know a plane flys the same in a low pressure system as in a high pressure system and the vacuum detected on the wings that provides the lift is not dependent on ambient pressure, but on the speed at which air passes the wing. Please feel free to point out any errors that I may have made as I really like fluid dynamics if you can't tell:rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao::rotflmao:

 

[Alittlefishy]

Well, it seems I had a few errors...that MJ1200 got me remembering that one time I had a seaclone on my 30" deep 140 tank. I did not like seeing the pump, so I extended the connection to put the pump on the bottom of the tank, but it would not draw hardly any air.:nuts:
I did a bit of research and found that the pressure created by the water in the skimmer body does have an effect on the air being pulled in. I did find out why and it is this:

For the pump to move water with out the air venturi, all it has to do is create pressure on one side of the impeller and a vacuum on the other. And it does this by spinning the impeller. On the vacuum side, vacuum is relative to the pressure side, and this is where my earlier thoughts got misguided. That vacuum is not really a vacuum, but an area of pressure that is lower than the output. And contrary to my earlier post, that area of lower pressure can definately exceed the ambient air pressure that is used to get the air down the venturi and into the pump. So to conclude, a taller skimmer would adversely affect the amount of air being drawn in to the pump. Thanks for the guidance. Just remember that it doesn't suck, it aspirates.:nuts::nuts::nuts::nuts: Sorry, bad lab joke.

I am glad this was brought up, because I would've been uber pissed if I had built the monster 10' tall skimmer and it would not pull air!:thumbup: Please continue on

 

[Alittlefishy]

Yeah, my example with the seaclone is off a little from our current discussion.

So from our discussion, the pump in 8 feet of water would pull less air, right??? because of the 8' of water over the pump???

 

[Alittlefishy]

Randy, So any water outside of the recirc loop and skimmer has no effect on the air draw, but the more water in the skimmer that's above the recirc pump does adversely effect the air draw.

Another ?...so why do "they" say that skimmers work better in 6-8" of water?

Jason, I have an Aqualifter pump if I did have to inject air, but I would rather not since that is just one more part to potentially break

 

[Alittlefishy]

Jason, can we get a pic? You say you are going to revise the bottom section, does that mean you will move the recirc pump higher up the tower?

 

[Alittlefishy]

OIC very good then, cant wait to see it in action.

 

[Alittlefishy]

SOOOO, to revive this discussion, if I had a 6" skimmer with a 24" tall reaction chamber, and I wanted it to be recirc, can the recirc pump be too big?

ie a sedra 5000 on the ASM G-3 and G-4 vs the sedra 9000 on the G-4x. The G-3 has the 6" body and the G-4's both have an 8" body, but the G-4x is about 6" taller. I use the ASM only as an example of pump size vs skimmer reaction chamber size.

The other side of this is that IF I use a sedra 5000, it gets about 700lph on average and that corresponds to a 3.5" neck and the sedra 9000 is around 100lph and would let me use a 4" neck. The 4" could be cool cause it would only use one adapter for the neck. On the other hand, if I stick with the sedra 5000, it would be overkill for a 3" neck and I could use that 4way drain on the randystacie link I posted.

 

[Alittlefishy]

so a sedra 5000 on a 6"x24" body. cool I need to get some 3" clear pipe for the neck just to make tuning easier. I have a question about uniseals are they pretty leakproof? like for an external skimmer? I haven't decided whether I want it in the sump or not.