My new DIY skimmer

[Shoestring Reefer]

johnrags1234 has it right. I forget if the bubbles collapse too soon before they can be collected, or if the micro-bubbles merge to form big bubbles too quickly, but the low surface tension in fresh water prevents a skimmer from working. Maby you could do a water change, and then add salt to the old water? Or mix up some salt water and add some sea food to it, to make a really nasty stew that would REALLY be a test.

Maby that could be a universal skimmer test: how many pounds of rotting fish can my skimmer design handle per day.

 

[H20ENG]

FWIW,
You can skim freshwater with a little different design. They are sold for ponds. They obviously do not work as well as for saltwater, but doable.
Most freshwater skimmers have naroower bodies and very narrow foam throats, so the foam can exhaust quicker. This, as mentioned, is due to the bubbles breaking down quicker.
Here is a little boring history of fractionation if interested:
Fractionation also came from the wastewater or chemical industry, like many of the filtration designs we use. In wastewater, a large, high pressure pump pumps water to about 100 psi, then to an interface tank. High pressure air is also sent to this interface tank. In this tank, the air difuses into the water.
The mixture is then sent to a mixing valve (in this case sludge is fed to the mixture), and let loose into the reaction tank.
As the water / air / sludge mixture flows into the reaction tank, the air is now free to expand and the mixture turns to foam (think of opening a soda water bottle).
This foam brings (most of) the dissolved organics to the surface, where a huge squeegee comes along and slowly scrapes it to a trough, and on to a digester.
This process is called D.A.F., or Dissolved Air Flotation. So next time you get a whiff of your skimmate, think of a mat of skimmate 100 ft X 25ft and 3" thick!:hmm3:
Now you know the rest of the story......

 

[werew]

Thanks for the heads up and the history!

Well corn nuts.... i'd have nothing to test my skimmer on.

Paul

 

[werew]

The box, working with acrylic

The box, working with acrylic

So far it's so so. I gotta say, you need SQUARE parts and VERY smooth edges to make boxes with acrylic.

Using my tablesaw to cut the pieces out and then switching to my router table to give the pieces final dimensions and a good edge... I discovered i've lost my "touch" using my routing table and tablesaw. None of the pieces were square, and my routing table's fence doesn't adjust wide enough to get perfect straight lines.

Total bummer to start off with... however i'm getting the hang of using the routing table on acrylic quite well.

The first 3 pieces together and it looks great, it's not that hard. When cutting this acrylic with the table saw, i've found it works best with the blade's tip 1/2" above the acrylic.

Paul

 

[werew]

quick question

quick question

I'm stumped.
I tried scaling, re-reading and cant find the answer anywhere. Jazzyreef asked it right before Cheapreef quit checkin up on this thread.

The heighth/clearance of the baffle. I cut my baffle so it has 3/4" clearance from the "lid"/top of the box, but i'd rather be safe than sorry. In his photos, it looks to be 3/4" to 1", but it's so hard to tell.

I know the top of the baffle goes into the bubble riser tower 1" or slightly less... I just need to know the clearance.

Would it hurt having 3/4" clearance using a MAG7 pump? So far, my dimensions are almost exact with Cheapreef's.

Thanks,
Paul

 

[satnu]

I also encountered this problem. I set mine 1 1/2 inches below where the top is attached.

You can't really go wrong I think. I just guessed and mine is whoopin butt right now. Beat $350 at the LFS!!!!!

 

[werew]

Satnu, question

Satnu, question

What pump did you use for your's???

I plan on using the Mag7.

I set my baffle @ 3/4" from the top (but could cut it down to 1" still as the lid hasn't been sealed to the box yet.

When you look at your's operating, can you guess if the 3/4" baffle clearance could interfere with it's performance? Just a guesstimate of what you think the difference is would be interesting to know.

Tell ya what, i've worked with gray smoke and clear acrylic... i'm going to avoid the gray smoke from now on. I read somewhere that it's the hardest to cut/sand because they use carbon as coloring. The carbon makes it harder I guess.

I have all the parts ready to assemble except 2. I have to form the nozzle still, and need a threaded collection cup ring to screw the cup's lid down onto. I'm not going to use a seal on the cups lid, just 4 screws.

 

[H@rry]

I made mine using roughly the dimensions of an EV180 (9 1/4L x 6W x 7 1/4H) and powered it with a Rio 3100. To make the spray nozzle I used thin wall 1/2 PVC (make sure it's thin wall). I then drove three nails part way into a board at an angle so it looks kinda like an upside down teepee. I cut a 6" piece of the PVC and heated the end 1" or so with a butane charcoal lighter until it started to scorch a little bit at the end and shoved it down between the three nails and held it a couple of minutes until it cooled. It takes a couple of tries to get the hang of it but the three nails will pinch it just right to make the cloverleaf nozzle. The nails need to be very close togather. To attach it to the "input riser" (or whatever it called) I cut a 1/2" PVC coupling in two and reamed it so the nozzle would slide through it and drilled and threaded a hole for a nylon locking screw. I then glued that collar to the top removable plate so I have about 3" of nozzle height adjustment.

When I first started it there was so much turbulance in the box that the water seemed like it was boiling. I didn't think there was any way for foam to form on top of that. I about 3 hours I started to notice a thin layer of "quieter" foam on top. By the next morning it had begun to overflow in the collection cup. The foam on top is very stiff and dry. The skimmate is very dark brown.

Now a question for the ones of you that have built one and have had it running for a while. According to the AquaC manual you need to wipe down the walls of the foam tower to remove the gunk. Is this not what I have waited to accumulate that allows the foam to climb to the top? If I clean it won't I have to wait for it to slime up again? Who cleans theirs?

 

[werew]

Harry,
Thanks on the nozzle forming tip. Sounds like an excellent way to form one!

How much clearance did you allow your baffle from the mixing box's lid? I'm down to making the last part (nozzle) before assembling mine and am curious as to what other's who've built this type of skimmer think about 3/4" baffle clearance to the top of mixing box??? Should I cut it down to 1" clearance, 1 1/2" ???

For the nozzle, I bought 3/4" thin walled PVC and used a 1/2" ID barbed 90 degree elbow that is threaded on the other end and has a recess for an O-ring. For the nozzle, I got a threaded to slip 3/4" fitting, so if I want to change nozzles out, it only costs me .22 cents.

Thanks,
Paul

 

[AQUAN8TOR]

hey guys. I cut my baffle about 1.25" from the top, and it works great. However, my skimmer is closer to the dimensions of the EV-240 or EV-400. the box is 11" tall, so perhaps your baffles should be more like 1" below. I made my roomate a skimmer of this design, and used 1" on the baffle opening, and it works great. I guess the baffle height depends greatly on how much water you're moving through the skimmer. I personally am using a gen-x mak4; I used a mag-12 for a couple months, and just wasn't satisfied. It's been working great for the last few months with no problems; I just wish I had made the collection cup a twist-on/off for ease of cleaning. It becomes a pita when you have 8 screws and wingnuts to remove every time you clean the foam tower.
Also, I made my injector out of 3/4" thin-wall, hth.

jazzy

 

[AQUAN8TOR]

sorry. meant to say 2.5 inches. don't know how I wrote 1.25. my fingers aren't working today.

 

[AQUAN8TOR]

Thought I'd add one more thing. The skimmer I built for my roommate has a little bit of 'splash' around the base of the tube. That is to say, that even when the skimmer is adjusted properly, and the foam is at the proper level, just below the top of the box, that the water movement inside the box is enough to send the level inside the box into the foam tube. This doesn't seem to affect foam production, but I would still have had a little more clearance from the top of the box if I had that skimmer to do over. Part of the reason for the large space between the baffle and the top of the box on my skimmer (12"x11x7") is that I'm using 1 1/2" pvc as the drainpipe, and needed extra clearance for the bulkhead and elbows. 1.5" pvc is already about 2" around, and the elbows are about 2.5". Leave this extra space before you end up needing it. as long as your exit (drain) tube is angled against the baffle, and close to the bottom of the box (1" in my case), that will keep most of the bubbles inside the skimmer and out of your tank.

 

[H@rry]

The top of my baffle is about 1 3/4" below the top of the box and and the back edge is almost to the center of the foam tower tube. If I make another one I want to figure out a little different arrangement for the baffle to cut down on the turbulance at the base of the foam tower.

As for as the collection cup, I just used stacking acrylic pasta containers from Bed Bath & Beyond. Since they have a lip on the bottom they stack and don't need anything to hold them down. Just pick it up.

 

[satnu]

Re: Satnu, question

Re: Satnu, question

What pump did you use for your's???

I plan on using the Mag7.

I set my baffle @ 3/4" from the top (but could cut it down to 1" still as the lid hasn't been sealed to the box yet.

When you look at your's operating, can you guess if the 3/4" baffle clearance could interfere with it's performance? Just a guesstimate of what you think the difference is would be interesting to know.

Tell ya what, i've worked with gray smoke and clear acrylic... i'm going to avoid the gray smoke from now on. I read somewhere that it's the hardest to cut/sand because they use carbon as coloring. The carbon makes it harder I guess.

I have all the parts ready to assemble except 2. I have to form the nozzle still, and need a threaded collection cup ring to screw the cup's lid down onto. I'm not going to use a seal on the cups lid, just 4 screws.

I am using a MAG 7 to drive it. I routed the top to accept an O ring and then cut out notches to "lock" it down.

 

[Cheapreef]

For all the pople that PM'd me and emailed about the pictures of the skimmer. The server they where hosted on went down, but i have the pics if anybody would like to host them i will link them so they are fixed. Sorry for the late reply to all those that have tried to get ahold of me, just haven' t been on the board for a while. I'll be here now if anyone has questions ect.

Clinton

 

[Cheapreef]

Here are some of the pics i had up, if there are anymore anyone wants let me know and i'll post them.

 

[bond007069]

where did the pics go

 

[juiceco]

please repost the pic's. great idea, thanks, Justin

 

[RobinsonFam1]

check their gallery. they (members) may not even be active anymore and the pics here may have died due to server upgrades and what not.

 

[juiceco]

thanks for the tip robinson, I am pretty comfortable with overall design but I would like to see a pic of the injector piece before before I start dipping pvc in veg. oil or playing with fire... if anyone has such a pic please post. thanks in advance, justin