New Pond

[Derwen Koi]

Hi All, I'm looking for some guidance I've an area in my garden that I'm hoping to convert into a Koi pond the surface area is 92" x 84" I could push it to 96" long probably and Iam thinking of a depth of 4 possibly 5ft deep and I'am thinking of using a box liner with a sunken type sump pump type sponge fitter piped up to a shop bought or similar box type filter which can be housed in a shed and then fed back to a veggie filter which will be about 12" wide by virtually the length of the pond 96" and then fed back into the pond which will hopefully house 6 to 8 Koi of about 4 to 8", I know this isn't the traditional type of build, but it seems the most viable way of me having a Koi pond at the moment and one that won't be that expensive.

Any advice greatly received and appreciated.

Thanks

[Airlite]

Hi Mate, an 8ft x 7ft x 5ft volume of water works out at a smidgeon under 1750 UK gallons which is a reasonable size in my book (mine's around 1500). It's worth having a look at as many ponds as you can before deciding on how to design/build your own as the devil is always in the detail and you'll save yourself a fortune in the long run if you take your time at this stage and plan your build really well.

As far as answering your question, the first thing I need to declare is that I'm a relative newcomer to the hobby myself. I built mine in 2015 in a corner of my back yard which backed onto my garage wall. It's a raised pond about 3ft above ground and 1ft below in a quarter circle shape with a EPDM liner. Mine's got a bottom drain which gravity feeds my filter but I've also got a submerged pump which runs at around 6000 lph which feeds my (raised) stream feature so I know the advantages and disadvantages of both types. So my first recommendation is this; if you can afford to spend the time, effort and perhaps a little bit of extra dosh your hard work will be rewarded with a bottom drain especially if you take a bit more time over the shaping of the pond floor. It's way more efficient and much easier to maintain than a submerged pump in my book. My second tip is this; if you use a sponge type filter you're not going to enjoy keeping koi for long as you'll either be spending all of your free time rinsing the incredible amount of cr4p and other pond detritus they collect, or you'll get fed up doing that which is when your water quality will start to suffer and that's when you'll start to wonder why your fish aren't thriving. Third tip; invest a some kind of pre-filter if your budget will stretch. A pre-filter is a "mechanical" filter that catches the aforementioned crud before it reaches whatever biological filter you decide to use. They range in form, size, efficiency and price ranging from your sponges at one end of the scale, then there's your vortex filters and brushes through to your sieves and at the serious end there's your rotary drum filters (these are generally thought of as being friggin awesome).

Final tip; if your thinking of a "veggie" filter then this is for you - look into anoxic filtration. Check out Manky Sanke's web pages on the subject and also look at some of the posts about it on this forum. It's super-cheap and fantastically effective if done properly (and frankly I don't understand why more people don't use it). I was skeptical of some of the claims about how an anoxic filter system works but I tried it alongside my normal bio filter and the combination is remarkable to my mind. I've got 18 unplanted biocenosis baskets but they work best when planted making the entire system easy to hide in plain sight as your veggie filter area. I wouldn't build a new pond without including one in my plans. Definitely worth looking into for your project I'd say.

Hope that gives you something to consider mate. Remember that I'm only a newbie myself so don't just take my word into account - have a proper look around, get as many different opinions as you can and then make up your mind about what will suit you best. One last thing; if you've got a budget in mind, double it, add 30% on top of that and you might just about be in the ball park if you're lucky (but most likely you'll still be short and you'll definitely wish you'd made your pond bigger once you finish it)!

Good luck with your build and let us know how you get on. Cheers, M

[Derwen Koi]

Thanks for the reply, I may have to hold back a while and re-think things, the Anoxic filter sounds a good way to go and it will give an ascetic look but how do you get the correct oxygen level to suit the anoxic?, what would you say is a good cheap mechanical option before the Anoxic filter? also views on using a box liner?

Thanks

[Airlite]

Hi again. Ok, last question first; box liner - on the plus side they're quick and easy to install, no creases etc and ideal if your pond is an awkward shape. On the down side, they're more expensive than a simple EPDM length of liner and your measurements have to be accurate - if you cock it up there's no taking it back! I've used a box liner in my QT tank (only 233 gallons, 6ft x 2.5ft x 2.5ft) just so I didn't have to deal with the creases in the corners

Regarding the mechanical pre-filter; it's hard to say because everyone's budget is different and there's other things to consider with this too like, how much room you've got, how much and what size crud do you want to remove, how much effort are you willing to put in cleaning/maintaining it etc etc, how much noise are you willing to put up with? When I built mine all I had was the bottom drain gravity feeding a two chamber filter - the first bay had 16 brushes packed in as the mechanical filter to stop big chunks of pond cr4p getting through to the next bay which contained layers of Japanese matting where all the bio action took place, and this was topped off by a layer of fine filter matting to minimise the amount of those smaller shitey bits being pumped back into the pond. That filter cost me next to nothing - I've got it spare now and it's free to a good home if you want it - but before you rush over to collect it, it used to take me about three hours each Saturday to clean it properly and, although it was an effective filter in that it kept the ammonia and nitrite levels down, it was a haven for mozzies and midges in the summer until I invested in one of those zappers you see in kitchens or butchers shops! Bzzzzzzzzz .

I replaced that filter a couple of months back in favour of an Oase proficlear premium compact drum which is superb but it was expensive to buy (although for me it's worth every penny - crystal clear water, even at night with the lights on, and no pesky midges!). I can't really advise on other mid-range types like the various sieves as I haven't got any experience of these but there's plenty of info available - again, it's one of those things that you'd need to research or see for yourself to see what's going to suit you best. All I would add is that pre-filters are a good investment but which type you decide upon depends on how you prioritise your time vs effort vs budget.

Right then, next the anoxic filter question. Don't worry about oxygen levels in the baskets, just make them up in the way Manky details in his guide and chemistry takes care of the rest. Have a read of this part of his article . Well worth the time and effort in my opinion as this WILL save you a fortune if you're patient but, again, it might not be for everyone so for the sake of balance I should point out that other filter systems are available.

Hope some of this helps mate. Good luck with it whichever way you decide to go and enjoy the journey! Cheers, M

[Manky Sanke]

I don't think you would find anyone in the hobby who would disagree with Mick (Airlite) about installing a bottom drain. A bottom drain is certainly worth the effort and expense especially if you can also slightly slope the floor towards it. Also I'd agree that sponge filters often seem to be a relatively inexpensive solution to filtration but soon become a maintenance liability.

Mick suggested thinking about an anoxic filter. Since I've been advocating anoxic filtration I've often been asked how to achieve a low level of oxygen in the anoxic pond but that is a misunderstanding of the anoxic principle. The pond itself is as highly aerated as the main pond and, as Mick said, the anoxic conditions are formed inside the baskets themselves by the biochemistry of the bugs that set up home in there.

I began writing about anoxic filtration in magazine articles and there was such interest that I soon was answering huge numbers of emails and forum posts. One forum thread went on for about 17 pages (iirc) before the owner accidentally crashed the whole site and it folded!! The latest article I've written (on the link Mick gave) attempts to crystallise and explain as simply as possible the many questions and misunderstandings that have arisen over the years so there's a lot of information in there. I've put the technical stuff into science panels for those who want to know the science so there's no need read them but, if you're interested, at least try to understand the general principles and ask questions if you don't understand.

Another bit of advise I often give to those who are thinking of making their first venture into koi keeping is to join a koi club. All clubs welcome new members especially those who haven't yet started and are looking for advice before they do. If you ask around, you will get invited to see some of the members' ponds and there is one question I always suggest asking - "if you were to start again, what would you do differently?" That question will help you avoid those ideas that someone thought would be good but didn't quite pan out as hoped - a bit like sponge filters!!!

[Derwen Koi]

Thanks both, I think I'll go down the sieve route and then the anoxic filter, one question though will I need any other filtration or a UV filter, I do intend putting a Pergola which may help the water clarity, also what size pump would you think will be needed for 1500 to 2000 gallons, also do I just rely on the flow rate from the return water from the anoxic filter to create the flow and oxygen in the pond? sorry for so many questions, I'm just trying to gather the basic's on which to cost it all.

Many Thanks

Steve.

[Manky Sanke]

Anoxic filtration is designed to be a stand alone system that will provide all you need for a koi pond without the addition of any other gizmos but it doesn't have to be the only equipment. Just like any other filtration system there are things you can do to make improvements. You won't be able to improve the water chemistry - the anoxic system provides everything you need in that area but, in common with conventional systems, a UV will prevent green water and a sieve or other mechanical filter will improve water clarity.

Turnover rate is a hot topic because it isn't possible to give a specific value that is ideal for all situations. Twin important factors are the stocking rate and feeding regime. My opinion is that the minimum turnover rate for a lightly stocked pond is once every two hours. Once per hour is what I would call a good turnover rate that will give good water parameters for the average koi pond but faster turnover rates are desirable with higher stocking and consequentially higher feeding rates. Your proposed pond will be between 6,800 and 9,100 litres so, for a one hour turnover, you would need a pump that will deliver 7,000 to 9,000 litres per hour after taking into account friction losses in the pipework and any head loss.

The anoxic pond will have (virtually) no effect on oxygen levels. The oxygen level leaving the pond will be the same as the level entering it. If you have a waterfall returning the water to the main pond it will provide some aeration, just as any waterfall would, but I wouldn't advise having a waterfall as the sole means of aeration with any filter system. A separate air pump is essential with any filter system, even those based on aerated K1 or showers or with venturi returns because, if the pump fails, the fish will also lose their aeration and, again depending on stocking rate, could suffocate within hours before you even notice.

[Airlite]

Hi Steve, a pergola's a nice touch and something I wish I'd done too. I'm not sure it'll help with water clarity though, other than preventing leaves and stuff dropping in but what it may help with is providing some shade which is good. Providing shade will help keep your water temperature a bit more stable and also minimise unwanted algae growth to a degree. It has other benefits too, like helping to reduce the effect of photosynthesis in your pond. What? I hear you ask - it's a long story and one detailed in several posts of mine elsewhere on this forum but the crux of the tale is that shade can also help keep your pH levels from varying wildly between day and night. 'Nuff said.

Most guys advocate using a UV as this will certainly help to reduce algae growth and help keep your pond looking clear. They're particularly good at stopping green algae, the stuff that makes your pond look like pea soup if left to its own devices, and especially so if you also have some shade (another good reason for your pergola). For a 2000 gallon pond it won't need be massive - something like a 25w unit would be more than enough I'd say.

Pump size - there's a lot of variables but it's generally considered that you should move at least half the volume of your pond water through your filter each hour. Personally, I pump around double that, i.e. the whole pond volume over an hour as I think that works better for me and I think most guys run at about that on average. I should say though, that in addition to that, I also have about half the pond volume each hour pumped over my little stream feature which augments the main filtration system as it contains my plants and has an alfagrog media base. On 1750 -2000 gallons something between an 8000 and 10000 lph pump will do the job under normal loading.

A pump that size will give you a reasonable flow back to the pond but it's always a good idea to budget for a decent air pump. Again, it's something most guys consider essential. There are times when it's really important to maximise the amount of dissolved oxygen in the pond in order to keep your fish healthy. In hot weather, for example. Also, some medication/anti parasite treatment require maximum oxygen levels during treatment so I'd say you have to budget and plan to use one in your build.

Regarding the extra filtration; that's a personal choice. The anoxic filter system is superb on its own if it's done properly and in accordance with Manky's article and that's easy to do if you're starting from scratch. I augment mine only because the drum I bought as a pre-filter has a small combined fluid bed incorporated in it anyway and also because I can't plant my baskets up currently as the tank they're housed in is in my garage. The beauty of an anoxic filter, apart from the aesthetic benefits, is that it costs literally nothing to run and will last for years. Design it properly and you can add baskets as you increase your fish stock, daily/weekly/monthly maintenance is not required and your water quality will be about as good as it can get.

Hope that helps mate. Cheers,M

[Airlite]

Ha ha Syd beat me to it! He must be a faster typer or he gets up earlier than me. Glad that he and I come to the same conclusions.

[Manky Sanke]

[Derwen Koi]

Cheers Both you've been very helpful, I was worried about the speed of the water going through the filtration as the water doesn't seem as if it would be in the filters for long enough to take all the bugs and bad stuff out of the water.

I have thought about the Eric filters as well and keeping a constant trickle, but I'll need to run waste water pipework to a drain then.

[Airlite]

[Derwen Koi]

The cost is going up everytime I think about doing it, I daren't tell her indoors, there's a Koi dealer/supplier of an array of Koi products, about 25miles from me, think I'll plan a trip up there and get some prices and try and gain a bit more knowledge, before as you say picking up a spade, although I'm thinking more of a mirco digger, I'm a bit out of shape for the old pick and shovel

[ginboomerang]

Your pond size will mean that the decision to heat will be a little easier and less costly. There are advantages to having a smaller pond.