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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