Different PVC Skimmer

[taekwondodo]

Thanks Randy!

Thanks for the tips - here's my "baby"...

Took about 5-6 hours, as I had to design the skimmer for the small sump (Need to redo the sump too - it's an overflow waiting to happen...).

Used 4" acrylic I got off of e-bay with 1-1/2" acrylic for the riser (both peices together were less than $20 - but had to use a few tricks to get the acrylic to fit the PVC). The collection cup I found at walmart - a small acrylic container.

Right now, I am not using a needle wheel, I am using a quite-one 1200 I had laying around and just using an aspirating venturi - seems to be doing quite well... Its been on a little over an hour and I'm starting to get real yellow foam belching over the top (previous skimmer sucked so bad (DIY) it was almost non-existent).

Again, thanks for the tips.

 

[RandyStacyE]

Looks like a rock solid skimmer to me! Isn't it surprising as to how well a standard impeller will work? I think needle impellers just make micro bubbles more efficiently than paddles do. They definitely reduce the flow rate of the pump, but can handle more air and chop air up better in return.

What size air line do you have running to your venturi and what venturi are you using?

 

[taekwondodo]

The input to the pump is 1/2" - I took a threaded/Slip coupling and drilled two 3/16" holes in it. I then cut two pieces of ridged airline tubing about 1" each, and cut about half of the tubing out of the end, about a 1/4" long, so that only a semi-cylinder was left of the airline tubing.

I pushed the airline tubing into the 3/8" holes in the coupling so that the backside of the cupped end of the airline tubing faced the flow (creating suction on the open end of the cylinder/cup of the ridged airline tubing).

See the drawing:

(edit: Hmmm. used the img button but am only getting a url to the picture)

Anyways,

IT started off great - initially got some yellow foam. Now, I think it's in "start-up" mode because all of the foam towards the top of the collection tube is "crisp" instead of like "beer head" (does that make sense?) - I also added carbon last night. not sure if that is related.

 

[RandyStacyE]

I assume your air line is 1/4" ID. That's all I use now. Be careful not to block or restrict the inlet too much or it can cause the pump to loose a lot of flow and choke on too much air. That can cause your 'venturi' to loose much efficiency.

If the pump chokes on 'too much air', though it still seems to be running ok, you can loose the ability to push a decent height. That can result in not being able to push the scum up into the up. It can produce scum, but not push it if you know what I mean.

I've found that if I back off on the air a bit, the skimmer produces more/better. It's strange, but you just have to find the sweet spot. I think all of the above depends on a well made venturi.

 

[taekwondodo]

Weird - most of the skimmer threads I'm reading people are bragging about how much air their skimmer is pulling through their needle wheels... or how many airstones they are using...

I'm pretty sure this is a start-up issue (but not 100% sure) because there is no head forming... just a column of bubbles (at work, or I would take some pictures).

How can I tell the difference?

- Jeff

 

[brianblack]

Initially you wont have a 'top foam' but give it some time. with the clear acrylic you can see where the 'foam head' starts least in my build I can. If ya want to see some of my pics http://www.reeffrontiers.com/forums/showthread.php?t=16248 I like the collection cup I had to make a drain in mine.

 

[taekwondodo]

So - if I want to replace the quiet one 1200 with a comparable needle-wheel, should I DIY the impeller for the QO? Is there a cost-effective alternative?

Thanks (Starting to foam now - but dang it's turbulent in the cylinder....).

- Jeff

 

[RandyStacyE]

So - if I want to replace the quiet one 1200 with a comparable needle-wheel, should I DIY the impeller for the QO? Is there a cost-effective alternative?

Thanks (Starting to foam now - but dang it's turbulent in the cylinder....).

- Jeff

There are ways to convert a stock impeller into a needle wheel. I started one quite a while back but just haven’t finished it yet.

I grinded off most of the paddles.
BEFORE:

AFTER:

I started with a 3M Roloc Bristle Disk, shorted the bristles, reduced its diameter and drilled a guide hole in the center:

I was thinking of doing something like shown below to help chew up the bubbles and get some more flow:

All I have to do is drill the appropriate size hole in the center and glue it on the impeller.

I was thinking of trying another one by just gluing on a couple of these 3M Roloc disks:

All that would be necessary would be to shorten the bristles with some scissors, drill out the center hole and glue it on with some superglue.

 

[brianblack]

Boy have the rolocs at work and never thought needle wheel Good idea - makes me want to play - have you seen the thread wheels?? I am thinking maybe the what are they called - I call them rice crispy wheels cuz they are bout the size of those patty things - plastic scuffy pad type wheel with a roloc. I will look for the official 3m name tomorrow if I can remember

 

[bradreef]

I would grind down the stock and add gutter guard. it is the new thing and has good results.

 

[taekwondodo]

Where can I pick a couple of these up?

 

[RandyStacyE]

I picked up the Bristle Disks up at Napa. I have absolutely no idea how they will perform I haven't glued them on the impeller yet. I will but I've been real busy lately. I believe Fastenall has them too. Many auto part stores carry them.

I was tempted to try the Gutter Wheel deal.

There are many cool ways to convert a stock impeller into a needle wheel, but many are quite involved.

Here is a cool looking one made from 'weed eater string':
http://www.reefcentral.com/forums/showthread.php?s=&postid=7852695#post7852695

 

[RandyStacyE]

Just a side note, I just tried a venturi I made for my skimmer. I took off the GenX venturi and put this one on:

I started with a 1" barbed fitting:

Cut off the barb:

Drilled a hole:

Then I inserted 1/4" ID tubing into it. It pulls so much air its rediculous. The barbed fitting only cost $00.50 at my local TSC. I think I'll throw away the GenX venturi, it totally sucks in comparison. I had to lower my standpipe as far down as it could go it made so much foam! After a couple of hrs later I was able to raise it back up a bit. I hear that the GenX venturis wer not that good, but I didn't think that they were that bad. I'm convinced now.

 

[RandyStacyE]

Boy have the rolocs at work and never thought needle wheel Good idea - makes me want to play - have you seen the thread wheels?? I am thinking maybe the what are they called - I call them rice crispy wheels cuz they are bout the size of those patty things - plastic scuffy pad type wheel with a roloc. I will look for the official 3m name tomorrow if I can remember

Do you mean this type?

 

[brianblack]

yeah that is it. I have some at the shop that are plain with no attaching roloc or anyother style. We don't use them cuz we all have the roloc on the angle grinder.

 

[RandyStacyE]

Yup "Thread Wheel":

That one seems to be quite a bit more loose than the 3M material though. I'm not sure, but I think that I read that a pump with the Thread wheel needs to be force fed (with water). I just recall reading that. It doesn't look like it could move much water - but would shred the heck out of air.

 

[brianblack]

Sounds kind of purpose defeating if ya got to feed it. Now would ya feed it water/air mix to chop it up even finer? I will have to watch here since there is a bunch here watching and waiting for them to hit the states. Think they may have hit just recently but not widely avail.

 

[taekwondodo]

Just an update - after 1 week, this skimmer is ROCKING. It took 2-3 days for it to get moving, and since then, I've emptied the collection cup twice (about a total of 1 quart (out of a 20G tank)) - nice tannish tea-colored skim.

Thanks!

- Jeff

 

[Skimmy]

Sounds kind of purpose defeating if ya got to feed it. Now would ya feed it water/air mix to chop it up even finer? I will have to watch here since there is a bunch here watching and waiting for them to hit the states. Think they may have hit just recently but not widely avail.

i havent heard of anyone having to do that with thier threadwheel pumps, there were some issues with the threadwheels in the american eheim pumps from ati, but they have moved to different, better pumps now.
some people who diy a thread wheel or gutter wheel might experience that if they screwed it up though...they have to be perfectly balanced and sized so that they will work the way they are suppose to.
i have an ati bubble master 150 on order so i'll let you know as soon as i get it, as far as the manufactured ones go...
also , like your make shift venturi, they work much better without the little post for the air line, the other trick i do is make the venturi out of the volute on the pump inlet, workes awesome!!

 

[DonW]

FWIW you really need to keep your ca down to nsw with the thread wheels/buffer pads. They seemed to collect ca deposits very fast.

Don