DIY Monster Beckett- Graphic Intensive!


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DIY Monster Beckett

Over the last few days, I built a large Becket Skimmer for my system (200 gallons currently, planed expansion to 500 gallons). I had made a much smaller downdraft skimmer many years ago, and this is an enhancement on that design.

Equipment used: Table saw with Acrylic cutting blade, router with flush trim and 1/4" round over bits, Vertical Mill with fly cutters, 14-20 tap and misc. hand tools.

I started with the base box. I drew it up in Autocad and sized it to handle the 6" main tube, and the single 3.5" injector tube. I used Weldon 16 to assemble it, and weighted it down to dry. Note that I should have cut the exit bulkhead hole before this step. :)
(All pictures located on my own server since I can't wait 3 days for them to upload to RC.)


Next was the fabrication of the top plate. I wanted to try a few tricks, so bear with me. It will all be clearer in a picture or two. I used a fly cutter to cut the two 3.5" holes, then used a 1" forstner bit to cut holes around one of them. I had to sand the hole a little to get a nice tight fit against the tube.


I measured out the 3.5" tube, cut 45 degree miters on them, and pushed them though the holes.
Next up was welding in the cross piece- This will force all the water that comes down the injector tube well up in to the 6" main tube, reducing greatly the bubbles in the output stream, and providing over 100" of water/air contact time.


Next up was the flanges. I drew up a pattern of eight bolt holes on a 7" circle, printed it a full size, and glued it down to a 8" square piece of acrylic. My mill has a rotary vice that allows me to spin it to any angle, then lock it down. I used the printout to align the mill to the exact center, then used the degree markings to drill the 8 holes for the first pair of flanges. The next part was trickier. I screwed the acrylic to the wood underneath and removed the clamps. Using a router bit in the mill, I routed the outside 8" edge using 2 passes. This gave me a clean edge, and as long as I was not "climb cutting" was reasonably safe. I finished off this set of flanges by using a fly cutter carefully adjusted to the 6" OD to cut the centers out of the pieces, then tapped the threads. This made the top flange on the main tube, and the flange the lid bolts to on the collection cup.


I completed the rest of the flanges- the 6" to 3.5" adapter flange on the base of the collection cup, and the lid on the top of the collection cup, and started gluing things together. Things went fast at this point. I was not able to make the "key-holes" that are a feature of other skimmers, but I think I have that figured out and will try it next time. I added in a 1/2" discharge port and completed the collection cup. I used a mixture of Weldon 4 and Weldon 16, depending on how tight the joint was. The bolts are Nylon 1/4-20.


I centered and attached the 6" tube to the base, and attached the base to the box. I water tested the 3.5" "U" first, and it was water tight. Then I caped the 1.5" bulkhead and water-tested the rest, and it held water too! I dried out everything well, and the next day finished routing and final assembly.

Next up was the beckett injector. My design goals were to run about 1000 GPH though the unit, and have minimal bubbles exit the unit, hence the tall design. I also wanted the beckett to be easily cleanable because I have heard they can clog up over time. I determined that a 3" PVC cap fits perfectly over 3.5" OD Acrylic tube and decided to use it. Until this point I had not used any PVC which gave it a more professional finish, but the time involved to make my own caps was not worth it. With a few adapter pieces, I came up with a design that uses a friction fit to hold the beckett in. In about 10 seconds I can have the top off the injector column and the beckett removed for cleaning, without any tools. Since this combination of a down-draft and a beckett pulls a slight vacuum, I added a CPVC air valve so I could control the amount of air entering the column.


Some more final pictures:
Top assembly:

Finished, ready for transport:

Running on my system:

Gunk from the test run:

I ran it for about 20 hours, then tore it down to take it in to the LFS (Ocean View Aquatics) for show and tell. I'm leaving it down there for a week or so then hope to take it over and set it up on a large tank and see if it will out-perform a commercial model.

Over all size: 49" tall, minimum of over 100" of water-air contact time, with a water capacity of around 8 gallons.
From the calculations I did, I expect this skimmer to easily handle a 500 gallon system. I will be building an auto-shutoff collection container for it next, then maybe on to a kalk reactor.


You just keep showing RC members that ANYONE can build these $?00 pieces of equipment with the right tools, some time, and some thought. Love the piece!!!

I do have one differing opinion, i love pvc!! I think it looks more "commercially-equipped" when it's decked out in sch. 80 PVC. That's my opinion though, more power to ya for your own thoughts.

Keep the pics flowing from your fishroom tanks and equipment.

really neat design Zeph. I like the way the return water flows through the 12 holes back through the base. I am not clear on the becket injector itself though. Can you explain more or provide some links to this injector. And just learning autocad myself, quite a learning curve to it as well. Can you make the dwg file available too or is this proprietary? Do you draw all your projects in autocad before begining to help calculate the materials? Thanks again for the amazing pics.
Is there a reason why you have the base in black acrylic? It would be neat to see this water flowing as well. Just curious.
pantinor said:
Is there a reason why you have the base in black acrylic? It would be neat to see this water flowing as well. Just curious.

Black acrylic makes it classy and professional looking.:p
you just don't stop do you!!!!!!!!!!!! how much was the total cost for equipment??? damn good job!!!!!!!
Thanks for the comments all!

Pantinor- The beckett (the black thing in the pictures) is available from places that have pond items. Technically it is a "pond aero-foamer", but works great here. I did do a rough 3D drawing Autocad to see what it would look like, but I just did the base and columns, I did not bother to model the collection cup and beckett. I have used Autocad for many many years, so it was a matter of minutes to draw it up though. It was certainly not necessary for this project, but it does help visualize a little, and helped me decided the order to build it in. For example if I would have glued the tubes in before building the box, I would not have been able to flush-route the edge on the top of the box. :)

I used black to prevent algae from growing in there. I have thoughts of putting a strip of masking tape vertically on the columns, and painting them too, then removing the tape to leave a "window" that I could see it with. I'm not sure that it is worth the effort though.

Schemo- I have not totaled the cost yet, but it is around $100, including the $20 Beckett injector.

Hi Zephrant,

Very impressed with all the DIY contribution of Zephrant. I'm not
a handy man but really getting motivated with this guy !!! Thanks Sir !!!


How did you size the skimmer? Is there some equations or rules of thumb that you used? Is it all based on contact time? Also, do you have a flow vs head loss curve for the becket? Reason I am asking is I have an idea and I need to size the thing to check cost.
Well, the sizing is really based on experience, and the room I had on hand. I wanted a single injector skimmer, to cut down on the cost of the pump/electricity, so tried to make up for that with an extremely long contact time. This skimmer is an oversized and improved version of a down-draft that I made many years ago.

I don't have a head loss curve for the Beckett- I used a LG4MDQSX because that is what I have on hand. Research I have done online indicates that about 1000 GPH though a beckett is the place to be though. I think a real pump (not an oversized powerhead) is really required to run a large Beckett skimmer effectively.


Great job on the skimmer.

I am now thinking of making one for my tank. How does a person figure out the size and flow for a particular tank. I have a 75 gallon tank and know that this would definetely be overkill.

Marm- I would skim the sites of companies that build them to get ideas- Most places put down the recommended tank sizes for their models, and some places even give some dimensions.

I have not come up with my own recommendations yet, or I'd offer them. :)

I'm shocked about the 3.5" piece with 2 bevel cuts on them.

I'm a draftsman, and occasionally I end up detailing tubular steel for large trusses. When a bevel cut is applied to a tubular piece, it's damn-near impossible for the other end to be bevel cut in the right plane. Think about it, there's so much room for error. It's not like there's a 'side' to a cylinder to help you to cut it. A piece with 2 bevel cuts often requires a massive amout of drawings and templates to wrap around the piece.

My hats off to you. That's some mighty fine work!! I'm very, very impressed.

Ewan- Lol- Yeah, it was a PITA to put those joints together. The two tubes must be at the perfect height, and rotated perfectly, then the cross piece has to be cut to the exact correct length... and the two 45's have to match simultaneously on both sides. :) I used the jointer to sneak up on the length of the cross piece.

The saving grace is that I used thick Weldon 16 glue, and it can fill small gaps. :)

A guy at work had an excellent idea though- Just use two 3" PVC elbows down there, with a short tube between them. Then I can cut square ends on the pipe, and slip it all together in seconds. So much simpler, and you can't really see it anyway.

Thanks for the comments-

Update- I was a little concerned about the design of my Beckett head- It allowed the foam to recirculate though the head a little, which kept it from being restricted by crusted salt, but it also reduced the amount of air going in to the system.

I made a new set of flanges (with O-rings) for the top of the injector tube, then inserted a baffle in the tube that the Beckett sticks though. I think that this has almost doubled the amount of air that the Beckett pulls in. I had to lower the water level 3" in the main chamber to keep it from flinging foam out the top that was way too wet. It is still producing foam that is pretty wet, but I'll see if it settles in.


Since the change, it has pulled out about 15oz of fluid in 24 hrs (medium Tea flavor), which is much more than before, but the previous skimmate was very dark, almost crunchy. :)