Hi Guys,
Just saw the thread or I would have replied earlier.
Here is the basics on the skimmer copied from the origional thread. Basically a variation of the downdraft skimmers. Plusses are no airpump and stones to be maintained, and no major restriction to flow like a spa venturi.
Dan
Trickle Tower/ Protein Skimmer
A few months ago I had a bio-ball partially plug the outlet of my shower filter on the basement pond and the water level rose to the bottom of the lowest tray. After a couple of days there was foam building up in the tray which gave me an idea for a protein skimmer ( of course someone else had the idea a long time ago
).
All protein skimmers work on two basic principles ( Someone correct me if I'm wrong. I've pieced this together from the back of sugar packets :yes:
).
1. Many undesirable compounds in our water are attracted to the air-water interface.
2. The more of these compounds that are on a bubble the longer the bubble will last.
Most traditional protein skimmers use these principals by injecting air into a chamber of water to get the compounds close to the interface so that they will attach to it. Then the bubbles rise up a pipe where they can concentrate the compounds as they break. They finaly exit the top of the pipe to a collection cup that is emptied or has a drain line.
This method works better on salt water than fresh because the bubbles produced in salt water are much smaller than in fresh and have a far greater surface area (There are probably other reasons, but I don't know what they are
).
The other way to get the same result is to spread the water very thin to get all of it close to the air. This is where the trickle tower comes in.
I had some 6" by 4" drain Ys around so thats the size I decided to use. The first two tries used 2.5 feet of pipe above the Y and 6 inches below. 1.5 inch bio balls are used for the media.
Both were placed in a gravity fed filter sump.
I wanted to see if the splashing action of design A would create more foam than B because I had to use plastic hardware cloth at the four inch opening on B to keep in the bio balls, and the foam would have to pass through this mesh.
There was a lot of foam produced, but the six inches below the Y wasn't enough depth to contain it.
I pulled out the towers the next night and changed them both to design C. Each tower holds around 540 balls.
I drilled the bottoms of the new pipe and fastened egg crate to them with ty-wraps.
I got the new design running about midnight and this was what had been produced by 6:00 am.
The good news is that these are on a shallow, overstocked pond in full sun and cleared the water from pure green :sick: to clear :yes: in about three days.
Since then foam production is way down but is constant.
I'd love to tell you how they work on a proper koi pond, but being that I don't have a pond like that I really wouldn't know. Obviously a pond with low DOC's in the first place would have less to remove, but if You had a pond like that then you already know about dimminished returns and a small improvement is that much closer to perfection.
I'll check the flows and report it later.
Dan