Simply Koi and More Koi

I don't know is you've seen on my 'build' thread (It's in quotes as no building has taken place for a long, long time...) but I'm planning a change of plan for my pond.

I was planning the bottom drain and surface skimmer to both gravity feed into a seive, then pump straight from there via a pipe pump over a shower and finally return the water via a 4" pipe back to the pond subsurface.

I'm now thinking of changing the filtration to static and fluidised K1 with an air powered return.

The skimmer and bottom drain will gravity feed into a settlement chamber (no room for a vortex).

There will then be a static K1 section in that chamber that will then feed into the fluidised sections. These will be two or three sections in series.

The final chamber will have, near the base, a 4" perforated pipe that will run out of the final chamber to return to the pond. The filter has a dry section between pond and filter where I will walk to clean the filter. The plan is for the 4" return to simply exit through the wall of the chamber, run along the floor of the dry area and rise vertically outside the pond wall. Near the top of this vertical section will be a tee and the tee will feed through the pond wall just under the surface. The open top of the tee will allow the airstone(s)/outlet(s) to simply be suspended at the optimum level in the vertical section to maximise flow and it will also allow the bubbles to gas off in the pipe, not all bubbling into the pond.

Hope that's clear!

So, the questions!

How much fluidised K1 will I need for a 5,000g pond with around 25 adult fish as a stocking rate?

Will 1 4" pipe give me a good rate of flow or will I need two? (There's 0 head using this design)

Any ideas on how to regulate the flow from the bottom drain and the skimmer? Both of these will feed directly into the settlement chamber. The bottom drain will come up through the base of the chamber and will be closed via a standpipe. The skimmer is just going to be sat in the settlement chamber (It needs to be sat there so it's right in the corner - and the whole is alreayd in the wall). How do I control the flow or shall I just try it and then add valves or a restriction to the bottom drain feed if I need to?

I would appreciate any thoughts on any of this guys.

Hi Ed

My pond is 5000 gallons and runs on an air lift system. Very pleased with it all now, but suffered quite a few teething problems before I got it right!

I'd suggest you have a good inch or so of the return pipe above the water line. I tried the return below the water line and the constant glug, glug of big air bubbles breaking the surface drove me mad!

Tried turning the T on the main vertical pipe upside down to try to make sure the air all went out the top (so the water sort of goes past the outlet and has to come back down??) but it didn't work! My return is now above the water level (bottom of pipe about 4" above pond surface) because it's the only way to solve it.

Also, you need to make sure the depth of the main riser pipe will allow the air to go deep enough to give you sufficient lift and flow. My return pipe leaves the aerated K1 chamber through the bottom and is effectively a U tube arrangement to give maximum depth of the main riser pipe.

Flow rate is plenty. Not measured it, but parameters are all OK and, with a 100lpm air pump, overdraws the 4" bottom drain on it's own. I have a gravity skimmer with a 3" pipe going into the same vortex and I get a good draw across the wier too. Here's a short vid of the return at about 9" above pond surface, so you can see there's plenty of flow - and even more when the bend is removed to reduce the head.



Hope that helps.

Good Luck

Bob

Hi Bob and thanks for replying.

I was planning to have about a metre and a half high vertical riser for the uplift. I like the idea of coming out of the base of the chamber! That'll work nicely on my design! Do you have a slide valve then to isolate the chamber for cleaning?

Interesting about the return pipe. How about if i raise the outlet so it enters the pond with part above the surface? I can't go higher than this without having pipework in the pond or having to come totally over the pond wall with a big, highly visible pipe!

How much media is in your system?

eds wrote:Hi Bob and thanks for replying.

I was planning to have about a metre and a half high vertical riser for the uplift. I like the idea of coming out of the base of the chamber! That'll work nicely on my design! Do you have a slide valve then to isolate the chamber for cleaning?

Interesting about the return pipe. How about if i raise the outlet so it enters the pond with part above the surface? I can't go higher than this without having pipework in the pond or having to come totally over the pond wall with a big, highly visible pipe!

How much media is in your system?

Hi Ed

Do you have a slide valve then to isolate the chamber for cleaning?
What cleaning? The airline is right on the bottom of the chamber and the K1 moves so much that nothing settles on the bottom - so never needs cleaning in my experience!

How about if i raise the outlet so it enters the pond with part above the surface?
Sounds like it will work because the air will be released above the water and prevent the large bubbles forming.

My original plan was to have the return coming up under the pergola in the photo below - but the constant glug glug drove me mad.
The return now comes over the edge of the pond and into the corner where it's hidden by the rockery and pergoda.




The pipe to the bottom of this photo was the original return. The current return can just be seen passing through the timber section of the pond enclosure.




BTW, the edge of the "shelf" where the rockery and pergola are is over 5ft long - and there's enough flow to make sure water flows over every inch of it!

Good Luck

Bob