# Discharge pipe location



## garryc (Jan 21, 2006)

The current discharge pipe of our pond is a Tee that sits at the maximum water level. It seems to me that it skims off the best water. Since we know that algea grows in the upper 12 inches of water, it would seem to me that if the water was discharged from that level it would discharge algea, and the phosphorous it contains. Just a thought.


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## [email protected] (Dec 22, 2006)

It doesn't really matter if you're using the bottom diffuser aerator but if you're not, you can just extend the overflow pipe to the bottom of the pond and drill a hole near the highest point so it can't start a siphon and drain the pond. There are bottom standpipe options too but not as easy to install in an existing pond and not really necessary for a small pond unless there's a lot of flow through. Yet another option is a siphon system and it could be smaller diameter pipe and installed through the existing overflow pipe since it will move more water but you need some slope on the outlet side to make it work.

Here's a basic drawing I made of how a pond siphon works


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## garryc (Jan 21, 2006)

At this point we will probably be using a bottom aerator. It would move about 8000 GPM if you believe the charts. So I guess the discharge point is irrelevant when it's mixed like that.

On another issue, Ted said a slow start up and shut down in winter. That was to keep the fish alive. I was thinking, to heck with the fish as they are just what we stocked this year (I think the big ones are already dead). So what would be the advantage of firing the system up from the start and letting it run all winter. Would that have a positive effect on the muck? We would stock as a new pond in May.


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## [email protected] (Dec 22, 2006)

Makes sense to me. I don't think the bacteria works as well at cold temps but some is better than none and keeping the "good" bacteria supplied with oxygen should keep them living. 

Supercooling to the point of killing fish is rare even in more Northern states. I'm basing this on recent South Dakota State University research. The most extreme supercooling case in an Ohio pond may stress the fish making them suseptable to disease but it's very unlikely that a significant amount of fish would die from supercooling here. 

I turn mine off every winter because my geothermal heating system relys on the warmer bottom water to heat my house and I enjoy ice fishing...otherwise, I'd just let it run.

BTW, there is so much water boiling up above my airstations that it's really tough to swim a raft up on top of it because the flow of water is so great. They move a BUNCH of water.


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## garryc (Jan 21, 2006)

Vertex says at 8 feet the air station will move 2178 gpm with 1cfm. I'll be running two stations at 4 cfm and given the law of diminishing returns I'd say each would move about 4000 gpm for a total of 8000 gpm. When I figure the capacity as a rectangular box 25 yards x 60 yards x 2.66 yards x 202 gpcy yards I get 805,980 gallons. The sides are rather steep so I guess the capacity at 650,000 gallons. That means the system will turn the quantity of the water over in 81 minutes or 17 times a day. Since most action is near the heads I figure total turn over 6-8 times a day. 

Reports I have read say the diffusers create a large crater in the muck. Since my diffusers will be 20 yards apart I would expect a major flow in the center of the pond where the two flows hit each other. Hopefully this action will turn two craters into one big oblong one, say 26 yards long and 6 yards wide. One report I saw said the craters where 18 feet in diameter and went to hard bottom, it didn't say how deep the muck was when it was started.


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## garryc (Jan 21, 2006)

Ted says that there is no reason to run the aerator in the winter. The bacteria doesn't do anything when the temp is below about 45 degrees. That decides that.

As far as discharge, it seems to me that if the pipe is run all the way to the bottom then as melt water and rain water comes in it will replace the bottom water. The melt water and rain should have a great deal of O2 in it. Since the water will be running over frozen ground I wouldn't think it would be picking up very much silt . I guess over all that method would be a good thing, but I'm not sure. There is already an overflow safety on that line which is basically an elbow off that Tee with a pipe coming up about 8 inches higher than the regular outlet. That will prevent siphoning.


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## [email protected] (Dec 22, 2006)

That's interesting about the craters. I never thought about what it would look like. That makes sense and is good to know if you're collecting data as to muck reduction.

Sounds like you'll have plenty of aeration!

Here's a picture that illustrates how much of the water is affected. Can you see the different densities of water?


















For comparison, my Vertex Air 1 Plus compressor puts out 2.3 CFM at typical 5.0 PSI operating pressure and according to the mfg. was tested to move "up to" 6700 Gallons per minute


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## garryc (Jan 21, 2006)

We will be splitting 4.2 psi to two vertex stations set at 8 feet. That should move 8000 gallons a minute. In a pond with a capacity of about 650,000 gallons that's 2 real good flow


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## garryc (Jan 21, 2006)

We will be splitting 4.2 psi to two vertex stations set at 8 feet. That should move 8000 gallons a minute. In a pond with a capacity of about 650,000 gallons that's real good flow


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