18'000 Litre Pond Build/Journal - (Filtration and any other advice welcome)

Hi, so after about 5 years of faffing about I finally decided to get cracking on a Pond. I decided to build roughly about 18'000 litres. It's about 22ft long an on average around 2.5 ft deep. I've been looking round at filtration and because I have dug out another pond higher up, to create a waterfall into the main pond, and keep a few fancy Goldfish in, I have been toying with the idea of 2 pressurised filters instead of a Nexus 320. The Nexus I don't think would be able to accommodate running into both ponds at the same time, or am I wrong?

The 2 I'd be going with are Allpond Solution 75'000 and an all pond solution 20'000. I know if the Pond is stocked properly with Koi this may be an issue, I plan on only having 3 or 4 Koi, an maybe a Sterlet, the rest just other forms of Goldfish. I know the Nexus is better long term, I'm just worried I'll still need to but another on top of it, to run off into the little pond from the main one.


Does anyone have any experience with these Allpondsolutons ones in Ponds? I currently run the 12'000ltre version in my big 2000ltre tropical tank an it seems to run perfectly, I just know ponds may be a little different.

I'll post some pics of the current progress at some point today or tomorrow too


Thanks, Vinny

A little view of what's been done so far.

This was the original area

As you can see, a phenomenal amount of large roots. Worries me a little moving forward, but this is the only area available unfortunately

Dug out the middle deeper bit is larger than that now, an its just over 3ft deep. I've added around another 2ft width to it

This is where I am going to put the waterfall from the smaller pond you can just about see at the top there. This pond is about 6ft by 5ft an goes to about 3ft deep in the middle, but shallower at the sides. I currently have some Moores an other fancy Goldfish in a small raised pond, I will be placing them in this one. I will be trimming those bushes right back too


Old trees we took out years back, it was a nightmare getting these stumps out


This is where I am as of now. Just need to finish up with the carpet an carpet underlay, then I'll be adding the liner underlay an liner, hopefully in the next week




Any other advice anyone can give would be very much appreciated

Looking good! Excited to see the finished product

So I’ve added Al other underlay yesterday. Ready to start trying to fit the liner today. First time doing this so should be interesting

This is awesome seeing about the progression !

Ide recommend you start a journal on this forum.

In terms of filtration you are aiming to filter 7-10x a fish tanks volume and I assume ponds are the same

So, a fair bit of progress made since my last update.

Filter wise, I have a Nexus 320 being delivered tomorrow, can’t wait to have a play with this. I ordered an Evolution Aqua95 for in the filter. In the pond I have a swell variable flow pond pump premium 20'000. The Nexus says it needs maximum 13’000ltre an hour, with pipe work etc, I think I can probably run this on around 80% an it should work well. I’ve bought the Blagdon pond oxygenator 3600 for air stones within the pond. This gives me the option of 20 air stones if I want, so lots of options going forward. I plan on using 3 of the 8 inch discs for now an see how I go. This may need to be improved if I do add the Sterlets. I’ve also added a floating Oase swimskim25 for leaves an floating material. This won’t be enough I imagine with the trees. Already having to fish out leaves twice a day. It has been really windy last 2 days though.

Below some updated pics. The delay in updates is because I'm having to do this all myself, in and around work. Helps I work from home, but still slow going on my own. My wife helps with little jobs like holding things occasionally




I ordered way too much liner, given the awkward space, it was a total nightmare trying to get it all in on my own



I started to build the cobble shoreline just to see how it would look.



Down the side of the garage, the filter will be placed down the end here. I was making this up as I go. It was a right mess here before

The opposite end, none of this is permanent yet, I'm playing round with ideas at the moment, all the flags and bricks were left over from 2 years ago when we had the back garden done. Handy we kept hold of them as they've come in very handy here

This is the difference. Been my last couple of days work. The 2nd pic was far from its worst too. I had to completely dig all that out. The near paving flag on it's side, will be like that all the way down, to create a border, an makes it easier to fill in around the edging pavement flags with cobbles. I will be running a fake stone edging mat right the way round the pond, so none of the liner should be visible under all the edging. That comes today or tomorrow, so I can crack on with that next, and put the paving all in place properly

Currently running the pump on its own, just to get the gases out. I've added the chlorine remover too and 4 airstones, just until I finalise it. Eventually, the seat will be built in to the cobble beach, but on paving and the circle stones will be steps up to the pond edge, and the seat.

Very nice...

Pretty awesome pond!

Looking great! What fish are you thinking about putting in it?

Sweet!
Thank you for sharing.

I’m not sure where you are located which will impact Koi. My research has been for Texas. Main considerations:
Hot weather climate Koi need deep water, about 5’, to stay cool in the summer.
The 2.5 ft depth should keep most birds from enjoying the fish. Better if pond has some top coverage so they can’t dive fish.
You’ll want 6-8 inches from the edge to the water level so the raccoons and other critters can’t go fishing…
Koi are very dirty fish so need a large filtration system. Rule of thumb is 20% volume of pond for the filter.
Pump is best positioned when pumping water out of filter. If pump is used to pump water into filter it will make waste particles smaller, making filtration harder…
Overflow should prevent fish escaping to streams, rivers,…

You might want to find a Koi club in your area to get local advice.

Enjoy you pond!

4Nines said:

Looking great! What fish are you thinking about putting in it?

Click to expand...

Im mostly gonna be going for Shubunkins, Goldfish, Fancy Goldfish with 2-4 Sterlets, however I've had a bit of a enforced change of plan short term. There was a guy in a neighbouring village who closed his tank down an needed to rehome 20 fish, they were all in a pond way too small, so I've now picked up 3 Koi, a couple of Orfe and the rest are a mix of goldfish/Shubunkins. I was planning on running his mature 6000 litre filter alongside my mature 4000 litre filter for them for a few days while I set up the Nexus, which is a 34'000Ltre filter. However he's cut all the plugs off so I'm having to wait for them to arrive, an they're currently all in it running off my little filter. It's not ideal, but they seem fine an I should get the Nexus going today or tomorrow anyway an run all 3 together for a while

I think I may end up moving the Koi an Orfe on at a later date, but not sure yet.

RoyW said:

Sweet!
Thank you for sharing.

I’m not sure where you are located which will impact Koi. My research has been for Texas. Main considerations:
Hot weather climate Koi need deep water, about 5’, to stay cool in the summer.
The 2.5 ft depth should keep most birds from enjoying the fish. Better if pond has some top coverage so they can’t dive fish.
You’ll want 6-8 inches from the edge to the water level so the raccoons and other critters can’t go fishing…
Koi are very dirty fish so need a large filtration system. Rule of thumb is 20% volume of pond for the filter.
Pump is best positioned when pumping water out of filter. If pump is used to pump water into filter it will make waste particles smaller, making filtration harder…
Overflow should prevent fish escaping to streams, rivers,…

You might want to find a Koi club in your area to get local advice.

Enjoy you pond!

Click to expand...

I'm in the UK, although the weather is cold in the winter, it will very rarely go below freezing so should be ok that side, the deepest part is about 3.5 feet an I dont plan on Koi so should be ok. There's a lot of carpet an carpet underlay below the liner too, so hopefully that will keep it a little warmer in winter.

The filter is 34'000 ltre (for Koi Ponds) an the pond is probably no more than 18'000, so should be over filtered

Update?