Thread: New Pond

Hi.

The drawings look pretty impressive. That would be great when built.

Have you considered adding a window in the seated area?

What type of fish do you plan to have?

If koi, than a 20k pressure filter will not be anywhere near enough to deal with the waste produced by koi.

If having koi, a drum (mech. Filtration) followed by a moving bed filter (bio filter) would be ideal, although other options exist e.g. sieve filter (mech. filter), vortex (mech filter), anoxic chamber (bio filter), nexus filter (mech. And bio filter).

Another thing to bear in mind, overspec any pump or filter. So if a pump says it shifts 20k lph, that is usually based on there being no backpressure/head loss. As soon as you pump water through pipes or above the pond level you will get less than the stated output.

Same for filters. If a filter says it can handle 20k lph, that is probably only if the water is clean (which it won't be). So whatever the stated flow is you need to add on 30 - 50% extra to ensure the filter can actually handle all the waste produced by the fish.

In terms of adding a shelf for plants.

Koi tend to absolutely destroy plants. But if the pond is sectioned up I.e. a series of connected smaller ponds, you could have one that is plants only, that would be fine and actually work as a good bio filter.

Also If you add a shelf, that would give herons a nice place to do their fishing from, so it's best not to have shallow shelves if you can help it.

In terms of bottom drains. You could not connect them. Because if you have one BD for the lower pond and one for the higher pond and they are connected, the water levels in the two ponds would level out i.e. the water level would drop on the upper pond until it was the same level as the lower pond. I.e. the lower pond would overflow.

Based on your drawings, you want the BD for the lower pond feeding back into the upper pond on one set of filters and pumps. And then a BD on the upper pond to be on a separate loop feeding back into the upper pond.

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Also in terms of a skimmer, if the upper pond overflows into the lower pond, you probably won't need a skimmer on the upper pond (as theoretically anything floating will end up in the lower pond, providing it can actually get over the spillway).

So you may want a skimmer on the bottom pond rather than (or in addition too) the top pond.

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I think a 60 cm pond depth won’t work for koi. Do you really mean 600mm?
You would get huge temperature fluctuations.
It would also allow a heron to easily fish for all of your fish stocks.

Your design also doesn’t seem to allow for having gravity fed filters.
Pressure filter would barely be enough for goldfish, definitely not for koi.
Gravity fed filters need to sit at water level, and you then pumpt the water from the filters back to the pond.

If you wanted to upgrade your filters, you will almost certainly have to redo your pipework. I think it'd be a mistake and you'd waste a lot of time and money by making do with small filters now then trying to upgrade them later. Koi filters are big. Plus you need to allow plenty of space for all the pipework, and it needs to be easily accessible so you can clean them etc...

In terms of location of filters, the area to the left of the pic (next to where it says inlet), or the top right (at the top of the stairs) would work for gravity filters.

But if the filter pit is below ground e.g. under decking, you'd need a way to be able to lift the decking so you can easily access the filters. With emphasis on the word 'easily'.

Your filter pit will need to be bigger than you probably envisage. For example I have a shed that is 6ft wide and about 7ft long and I can only just get all the filters in it.

In terms of lighting, definitely don't have submerged lights. They're way more of a faff than overhead lights. If you added a pergola over the seated area and the pond area adjacent to it, that would provide a perfect place to add overhead lights so they illuminate the fish from the right angle from where they will be viewed i.e. you don't want the lights at the back, as it will put the front of the fish in shadow.

In terms of seeing the fish, that will depend on what filters you have. You need filters that can extract nearly all of the solids in the pond. That amount of water filtered through a tiny pressure filter would soon get murky with all the waste. Plus you'll need a UV filter to avoid the water going like pea soup from free floating algae.

Have you costed this project up? I can see it very easily going over £20k. For example, due to the irregular shape of the pond I'm not sure a box weld liner could be made (I maybe wrong on that point) so your main option to line the pond will be to fibreglass it, which isn't cheap, even if you did it yourself (which is what I did).

Other things to consider are how you will get water supply and electricity to the pond, and also how you will deal with all the dirty waste water (as you need to do a fair amount of water changes to keep koi healthy).




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