DIY Skimmer Critique

[rustybucket145]

Hi All! I'm in the planning phase of building a new skimmer for my system. I've found a plan that I 'almost' like well enough to go for. Will you please look at the link below and let me know what you think of the overall design of this skimmer.

I do plan on some modifications to this plan (space permitting). I want to go with an 8" body instead of 6" and I will be using a mesh modded GenX 40. I want to setup the pump to be recirculating and have the skimmer fed from the overflow from my display tank.

Also I want this skimmer to be setup outside of the sump, what are the chances of the uniseals leaking? Is there a better way to get the pipe in/out of the body?


My system is roughly 150gal total volume with 90gal display and a 40gal fuge/prop tank. I have a 30gal sump that's absolutely packed to the max.

Here's the link to the design I'm considering:
http://randystacye.com/diy_needle_wheel_skimmer.htm

Here's a pic of the recirc setup. Of course my pump will be situated a little differently than in the pic. I plan on using a gate valve to restrict the flow of water through the skimmer. Does it matter which direction the water comes into the skimmer? Should I 45 or 90 it to point in a certain direction? right? left? down?

Thanks in advance for any input.

[RandyStacyE]

Instead of using Uniseals you could drill thread the hole so you can screw a fitting in there. This fitting (like a bushing) can be modified to allow PVC pipe to be pushed completely through the bushing so you can put a 90 inside the reaction chamber. A little thread tape and you're all set.

I like Uniseals and I'm sure they would work, but If I were to build a big skimmer for out of sump use ... personally I'd be tempted to NOT use them.

The gate valve would be an excellent addition.

Since you're thinking of using 8" pipe, how do you plan on making a cone for the top of the reaction chamber?

From what I've read on Euro-Reef.com, they suggest 1.5 - 2 times total system volume per hour to be your flow rate through the skimmer. Assuming that is accurate, you would want something like 225-300 gph.

I started a thread a little while ago RE: "Feeding A Recirc Skimmer". There may be some info there that may be useful.

To know if you are geting enough water through your skimmer you would want to be able to adjust this volume (using a valve) and measuring 1 gal of water from your overflow and timing it. You would want to be able to fill a 1 gal jug in 12-16 seconds to meet the range of 1.5 - 2 times your system volume.

[rustybucket145]

Wow! From the man himself. Thanks for your helpful comments.

I already feed my skimmer from my overflow, so all the plumbing is there and ready to plug and play with slight modifications (addition of gate valve instead of ball).

On the 8" pipe, I was hoping to find an 8" --> 6" reducer that would kinda 'neck' down in a sloping manner rather than step down. I could then use the floor drain that you have listed. I haven't located a reducer exactly like what I need yet but I should be able to find something that would suffice.

I'm also looking at having a skimmate drain tube connected to the cup. So the cup will drain into a larger vessel. I have also considered a 'wet neck' addition that would allow me to wash down and flush out the cup without having to completely remove it. Is the acrylic on the collection cup thick enough to drill and tap for a hose barb fitting? It's hard for me to tell from the pictures.

[RandyStacyE]

If you do find a reducer coupling from 8" to 4" or 8" to 3" you could just stick with that. I'd chop down the reducer coupling if you can using a saw. You don't need all that extra plastic with the slip fitting, just enough to slip and glue. It will be plenty tough once glued.

I wouldn’t necessarily use the reducer coupling and drain fitting you can find the appropriate reducer coupling (from 8" to whatever diameter neck you want). You'll find that whatever reducer coupling you find will be VERY pricy and having to buy both ... well you know what I mean.

When I first made my skimmer I exhausted all resources to find a nice transition from 6" PVC to the union. The drain fitting looked the best, was definitely the cheapest, required no tools and was the easiest solution out of any other method I've seen.

If you do have to use the drain fitting, I would chop off the top until it is flush with the dome. Now you can use a 3” Union instead of a crappy little 2” union/neck. I suppose you could even use larger than a 3” union and neck.

That collection cup I used is NOT going to be tough enough for what you want to do. It’s too thin and fragile for drilling/tapping threads. I’m sure that it’s not impossible to use rubber grommets and such (to plumb through), but I wouldn’t suggest it.

I once read a thread where a guy says that he found some large acrylic jars at a store called “Linens & Things”. I haven’t checked it out yet, but just be on the lookout for a large plastic container

Hopefully others know of a better container to use!

[daytonians]

Collection cup: go for the large tub of pretzel at you local grocery store. You get a great bottle for $5.00, and free pretzels to boot.

You could have part of the water from your display drain into a skimmer that size, but not nearly all of it. It would be moving too fast. Also, the drain wouldn't handle it unless it was huge.

Personally, I wouldn't go with anything less than 2" diameter skimmer drain. The water can easily flow out at 200 to 300 GPH without backing up in the skimmer.

I don't like valving off a skimmers drain.

[RandyStacyE]

Originally posted by daytonians
Collection cup: go for the large tub of pretzel at you local grocery store. You get a great bottle for $5.00, and free pretzels to boot.

You could have part of the water from your display drain into a skimmer that size, but not nearly all of it. It would be moving too fast. Also, the drain wouldn't handle it unless it was huge.

Personally, I wouldn't go with anything less than 2" diameter skimmer drain. The water can easily flow out at 200 to 300 GPH without backing up in the skimmer.

I don't like valving off a skimmers drain.

So you prefer to use a stand pipe to control the water column within the reaction chamber over using a gate valve?

Right now I'm about to make a 4" diameter version (of the drawing above) for my wife's 38 gal tank with a sump. I'm going to make it a recirculating and eventually using the mesh mod.

I've been trying to decide whether to go with the stand pipe or the gate valve for the initial build.

I agree with your suggestion. With such a big skimmer it would be wise not to restrict the output. I may have restricted the output by using a 1-1/4" stand pipe on my 6" skimmer, but I don't know for sure ... the 1-1/4" stand pipe I used was just a shot in the dark on my skimmer.

[daytonians]

Yes, I prefer the simple stand pipe. You can see exactly where the water level is by the height of the tube. You can put graduation marks on the pipe and raise or lower the water level precisely the amount you want. No guessing.

Also, I've had things collect at the valve and change the flow resulting in the water level going up. I don't use a pre-filter sponge, so particles do go in and come out.

As for size. I can tell you that the input pump I'm using pretty much maxed out 2" pipe. I added a second Venturi so it would suck more air and less water. That got it down to the flow I wanted. That is not a very large pump. I don't know who makes it though. I'm guess that I'm putting 200 to 300 GPH through the skimmer and back out.

[rustybucket145]

Ok, I understand that my skimmer can't handle all the water from my display. I already have the overflow line T'd, one end goes to my current skimmer and the other loops up and then flows into my sump. So the end of the T that goes to the skimmer will always have a supply of water.

I would think that 1 1/4" pipe would handle 200-300gph, don't you guys think? I'm not sure where to get the flow rate from but I'm sure somebody else has one.

I won't restrict the output of the skimmer, just the input (from the display). I was planning on doing this with a gate valve and a true union. The union will be directly after the valve so I can dis-assemble the union and clean the valve if needed. This union will mainly be used so I can easily remove the skimmer from the system.

So you think I should go with a larger neck? I don't guess it would be a problem, but would it be good or bad for skimmate production?


Ok, so next question. Here are some pics of my pump that's mesh modded and will be powering this skimmer. So I guess it would be good to get your opinions on this. Since I mesh modded it, it absolutely will blow the top off of my Berlin Skimmer XL, it's insane how many bubbles this thing will produce. I had to valve the air intake almost down to nothing b/c the berlin just couldn't handle it.

So, what do you guys think?

Before Mod


During Mod




After Mod

[rustybucket145]

bump, for a nightime post.

[daytonians]

Nice work on the pump. Let us know how it works on the new skimmer.

As for output: I would go bigger than 1 1/4". You have to keep in mind that the water is flowing through at least on elbow, and then up the tube. That is totally different than flowing down where it's own weight creates a siphon effect. My first snailman type skimmer started out with a 1" output. I didn't like that, so I rebuilt it with a 1- 1/12" output. That still seemed too small. Again, I rebuilt it with a 2" output. Third time was the charm.

I'm not really familiar with that pump, but if your getting as much air as it sounds like, I think a neck somewhere between 2" to 2.75". At least 6" long. The one I used was more like 9" long.

Here is a diagram of my skimmers top. It really made a difference.

[rustybucket145]

hmmm..... interesting.....

Do you have any pictures of this lid in action?

I'm also having trouble picturing the pretzel jar. Do you think you could find a similar one online for me to reference?

2.5 inches sounds good to me for a neck, but is that even a size of pipe that is readily available?

[daytonians]

This pic shows the jug and the lid pretty well.

[rustybucket145]

that's a big honkin skimmer & cup!!

Is your neck 2"?

[daytonians]

The neck is 3" on the outside. It's about 2- 5/8 or so on the inside.

[rustybucket145]

So it would be the same size as 3" PVC? Also, why did you do the cone of hot glue? Was the inside of the skimmate bubble column collapsing?

[daytonians]

Yeah, without the neck tapering, the bubble column was collapsing before it reached the top. I had to keep the water level up in the neck itself. Now with the cone, I have lowered the water level to about an inch below the neck.

The cone does the same thing as a tapered neck. It makes the area inside the tube smaller as it goes up.

Before the cone, the bubbles would collapse if the column was more than about 6 inches. Now the column is more like 11 inches tall and stays stable, and I get really thick dry skimmate.

[rustybucket145]

Do you think having a 2" neck would keep the column from collapsing?

[daytonians]

I really don't know. It would seem that any column will collapse at some point, if it is not continuing to condense in on itself with some form of tapering.

I think the main thing would be the length of the neck, and how dry you want your skimmate to be. The longer the column, the drier the skimmate. It worked without the cone, but I had to keep the water level higher, and run it much wetter.

Hopefully someone else can chime in with a more scientific answer for you. I just tried to copy what I've seen work on other skimmer, made a bunch of somewhat educated guesses, and probably got a little lucky also. lol

[rustybucket145]

Ok, here's my plan for reducing from 8" to 2" (or possibly 3" I haven't quite decided yet....) I've located these reducer couplings at a local plumbing supply house. What do you guys think? I will probably have to shorten the body a bit just for this to fit but it shouldn't effect the skimmer too much I wouldn't think. I will also be cutting some of the coupling portion of the reducers off in order to shorten them.



drawing not to scale, just sketched up.

[daytonians]

Yeah, that would work. That's what I did on my snailman skimmer.

[RandyStacyE]

Wow! Did you price those reducer couplings yet?

Honestly ... I wouldn't use a 2" neck on such a large skimmer. If you look at the specs on most if not all skimmer that size, they will likely have a 3-1/2" - 4" neck. I'd likely use 3" myself.

Some very experienced skimmer builders have critiqued the skimmer I built and suggested a larger neck on mine. I have no complaints, but they said that a small neck limits the amount of air and evidently helps to increase the concentration of the organic compounds in the foam or something like that.

[rustybucket145]

Ok, just got back from a scouting trip to the local ace hardware store. From my measurements under my stand 8" pipe will fit..... after looking at it I'm starting to have doubts.....

I can go from 6" --> 2" for under $20
I can also go from 6" --> 3" for roughly the same price.

So I'm starting to lean toward the 6" body of the skimmer. I really think that it's all that I'm going to have room for. I might however make it a little taller as my stand is close to 36" tall. Would increasing the height also increase skimming ability? ie, skimmer is rated for 135gal, I have 150gal+/-. I would like to oversize if possible that's why I was wanting to go with 8" pipe. Will increasing the height of the skimmer offset the size of the system?

Just from looking at the 2" pipe, It looks like it will be plenty wide enough for the skimmer neck. But if you guys really think that 3" would be better I guess I might go with that.

[daytonians]

Unless your budget just won't allow it, I'd go with the 8" body, and make it as tall as you can. The bigger it is, the longer water is inside being cleaned. That is one of the primary goals in skimmer design.

You can never have too big of a skimmer, but you can definitely have too small of one.

[rustybucket145]

Ok, after some further research have decided to go with the 3" neck. Plumbing supply house is looking for a single reducer to go from 6" to 3" with one fitting. They said if they didn't have it they could probably order it. So I figure one fitting is going to be cheaper than two. Anybody ever heard of a 6x3 reducing coupling?

[rustybucket145]

Well the budget isn't the hold-up, it's the room under the stand that's the holdup. I have to have room for my 30gal sump a return pump, the skimmer and skimmer pump. All this under a 4' stand.

When I was under the stand measuring it looked as though it was going to work but now that I have actually seen the pipe, I'm seriously worried. I'm gonna try to get a sample cut of both the 6" and the 8" pipe so I can see exactly how big it will be under my stand. But right now I'm thinking.....

30"+ tall
6" diameter body
3" neck
1200gph recirc pump mesh modded
1.5" skimmer drain on adjustable stand-pipe
Uniseals to seal all pipes entering/exiting skimmer body.