Creating a "still return"

[david_a]

Need some help guys and gals.

I've got a nexus 200 and 300. Importantly both pump fed and are above pond water level.

They both join into the same return of 110m pipe.

Theres probably around 20,000lph going into and therefore out through the return.

All working great, clear water etc etc. However.... the return is quite powerful.

If:
- I put a 90deg bend on and return it down to the bottom I get lots of bubbles (seems to create swirls in the 90deg) and these rise creating big ripples / waves
- If I return it across the top you could surf on it
- If I put a 90deg bend on it and return across the top you get loads of ripples/bubbles etc.

I'm after a still mirror like finish, I have a lot air going into the pond overnight and can put it on during the day in case of a heat wave / high temps / low oxy. So during the day I don't want any surface movement at all.

Help! How do I get it to return without affecting the surface?

Dave

[Gazza]

Hi Dave,

I very much doubt you will be able to get a very still pond surface and if you did then there is a possibility that the pond would not be getting filtered properly,I know some put a sock like piece on the end of the pipe may be worth a try.

[Casper Chapman]

Hi I am running 27000 litres over the side of the pond without too many problems.
What I have done is put a 45 deg elbow that is below the water level, but have a large hole in the top of the elbow to get red of excess air. What you can also do is put in a vertical pipe a bit like a chimney in the return pipe that is higher than the Nexus to remove air.

Good luck.