DIY Foam Fractionator . . .

[KoiCop]

Bought an additional air pump (Hi Blow 40 lpm) last week to add supplemental air to the pond and was running it with 3 large, round Japanese airstones. We already run 160 lpm between the two aerated bottom drains and the two upflow J-mat bio chambers.

Then I got a bright idea: I'd make one of those DIY foam fractionators (they're also called protein skimmers) and really put the new stones to good use.

I reviewed a diagram I'd recently seen on Koi Chat and off I went to the local hardware store, where a helpful floorman helped me find the requisite parts, glue, etc. in the ABS section.

Put this together in under 60 minutes for about $30 (and I'm not a DIY guy).

While it works great, getting the proper 'flow' by balancing the pond's level, the foam spout's height above the water level, and the amount of air upflowed in the main tube has been 'entertaining' to say the least. Some combinations fill the 5 gallon bucket in 5 minutes -- while others won't fill it in 24 hours.

I've had to turn off one of the two stones in the main tube and raise the unit two inches to get what I think is an 'optimum' flow rate (as judged by the color of the water in the bucket).

When the weighted air line I ordered gets here, I'll replumb the unit and run with two stones in the pond and only one in the FF. I'll also move the air pump and eliminate the bucket; I'll run the dischage line directly to an adjacent planter.


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R to L: Cap (3" rubber), upper spacer (3" ABS, 4" length), upper T (3" x 1 1/2" x 3", drilled with two 1/4" holes for airlines), clean out plug (threaded, 1 1/2", drilled with nine 1/4 " holes for air lines and for foam to exit), extender (1 1/2" with threaded top), reducer (3" to 1 1/2"), lower spacer (3" ABS, 3" length), lower T (3" x 1 1/2" x 3"), main tube (3" ABS, 24" length). The two arms (upper = waste; lower - water return) are 1 1/2" ABS.

I later had to add a 6" section aimed downward to the return arm and point it downwards to keep the air in the main tube from exiting with the discharge water. I also increased the length of the spacer between the discharge T and the reducer from 3" to 8" to increase the bubbles' dwell time in the main tube.


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. 36" ruler for comparison


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. Voila!

For anyone that doesn't completely understand the principles involved, here's an excellent link:

protein skimmer: Information from Answers.com
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[dubtaco]

Good work, I've been wanting to build one for some time now...

[koiczar]

Don

Nice job.

A question - Does that foam come out rather "wet" or "dry"? I notice that your bucket photo has quite a bit of water in it,albeit rather dirty.

Irwin installed one of the new commercial units on his pond and the foam comes out really dry. Also, I know you mentioned it in another thread somewhere, but how many gallons is your pond?

Thanks for the answers

Mike

[KoiCop]

Chris . . .

Thanks! Coming from a fabricator like you it means a lot.

Mike . . .

Our pond is 6K gallons. The foam is wet.

Airstone FF's are the simplest in terms of technology (check out the link I provided if you haven't already); they're also the least efficient. But they're dirt cheap and easy to build, have no moving parts, and cost nothing to run -- since they're 'powered' by an existing stone, etc.

I'm sure Erwin's unit runs rings around mine.

By the way, what brand did he get? What did it cost? And does it use electricity?

[RobR]

Don, I built a unit that is very similar and put it into service about 3 weeks ago. 4" pipe for main body, tapering to 2" at the top. A large AES diffuser for the stone and T'ed it into an existing air pump. Used 2" for overflow and waste.
So far not a damn bubble has come out of it. I mean nothing. I can hear it churning almost like a belching coming from it but no bubbles. If I turn up the air any more it pumps water out big time.
I'll try tweaking the placement of the unit and maybe cutting some air since I can't add anymore or else it acts like an airlift pump.
Any tips to get the foam?
I did notice that my return overflow was lower than yours, so I raised it. We'll see what happens tomorrow.
BTW Did you have problems with surface foam to start with? I did not but just like to tinker around. Maybe my DIY TT's are rendering this unit inoperable?

[aquitori]

Quote: Originally Posted by KoiCop I'm sure Erwin's unit runs rings around mine. By the way, what brand did he get? What did it cost? And does it use electricity?

Erwin got the Clarity (good for 10,000gals) unit from the UK...He has an external pump to run it...His water is super gin clear from what he has told me...And the foam is like super dry...

[KoiCop]

Hey, Rob . . .

The three main variables I played with were the pond's level, the foam spout's height above the water level and the amount of air upflowed in the main tube; minor variables were the length of the spacers and the main tube; I didn't have to play with the diameter of the foam chamber.

The foam column has to climb above the water's surface to exit; that's the critical distance. So, to increase the flow:

1. If the head of the unit is fixed, try raising the pond level to shorten the distance the foam has to travel to exit out the spout.
2. If the pond level is fixed, lower the unit's head to decrease the distance.
3. Adjusting spacers lengths can decrease the distance to be travelled.
4. Reducing the diameter of the chamber the foam rises in will allow it to climb highter.
5. Increasing the distance the air bubbles travel in the main tube allows them to attract more impurities, thereby creating thicker foam which will then be able to climb higher.
6. Increasing air flow is the simplest way to adjust -- but as you pointed out, it has limits, too.

Hopefully, one (or a combination) of these variables should solve your problem and get that sucker foaming.

Good Luck,

PS -- And, yes, I was getting a little foam under our waterfalls.

[KoiCop]

Thanks, Tony. I just went and checked out that model; it's in stock at Cascade.

By the way: How much is 675 pounds British in US dollars these days?

Wonder what shipping would cost?

[koiczar]

Don

If I'm not mistaken, the unit designed for a 10,000 gal pond (the one Erwin got) was about two grand!!!!!

Mike

[aquitori]

Quote: Originally Posted by koiczar Don If I'm not mistaken, the unit designed for a 10,000 gal pond (the one Erwin got) was about two grand!!!!! Mike

I think that was whole sale price...