New Pond Planning - Filtration, Bog and Planting.

[Andy41]

Hi Guys,

It's been a while since my last post, and all the plans i had at the start of the summer have been put on hold by a small (hopefully) planning disagreement with the council..... but, on the plus side that gives me more time to plan this properly

So, the basic idea here, is an egg timer shape pond, with a bridge in the middle. At one end will be a small bog garden, and some lillies, and at the other end will be a mass of reeds (both for filtration and for privacy screening from the road).

I've added a pic of the garden so you can get some idea of the pond. The external filtration will go into a wooden enclosure at top top right of the pond next to the fence. I'm also planning a small raised hill (using natural stone) next to the pond that will have a waterfall running down into the main pond. The bottom of the pond is slopped so that the deepest point will be under the bridge. I'm going to use a retro drain from there that will run to the pump in the filter enclosure. The pump for the waterfall will be in the shallow reed area.

The pond is 8m (24') from left to right, 5m (15') at it's widest, and 3m (9') where the bridge is. It's about 1.4m (5') deep. This gives me an approximate volume of 52000 litres (14000 gals). I'm only going to stock the pond with goldfish, not Koi.

So, the most important thing now is planning the filter system. I'm planning on using a Vortex filter to seperate out the solids, and then two skippy biofilters in series. There was a post a while ago about calculating the size of the skippy filters based on turn over and pond size, so i've used those to calculate the filter size.

Pond Turn over : 5x / day
Pond volume : 52000 l (14000 gal)
Flow rate : 11000 litres / h (3000 gal / h).
Biofilter retention time : 10 minutes.
flow rate and retention time give me a skippy filter volume of 1800 litres (476 gal).

This is way to big to be practical, so i've assumed that the planting in the pond take care of half the biofiltration, which then gives me a filter volume of 1000 litres (250 gals). This is still a lot though.

I'm planning on using 2" piping throughout.

I'd like to reduce the biofilter size more, but i don't see a way at the moment. I'd appreciate any ideas for improvements anyone might have. For example, how much does the bog garden contribute to the overall filtration? Can anyone put a number on it? If it's enough then i might get away with reducing the biofilter even further.

cheers,

Andy

 

[sissy]

Welcome back and have you planned it withstand the cold weather as you may need something to keep a hole in the ice and remeber if you are planning on building the bridge you may need footings to keep it from sinking down every time someone walks on it ..Thats going to be some build you are undertaking and would be interesting to see .Remember insulate your piping and don't run it where you can not access it if there is a leak and run a wire along it incase you can't find it as a metal detector will help you locate it .The first time I did my pond I did not do that (live and learn )I used mulch around my pipe it is easier to dig up and helps insulate them too . I also took plenty of pics of all the piping and how and where it runs to and also drew it out on paper .

 

[Waterbug]

I'd be interested to hear what issues the local council had. Sometimes I hear things we've not considered here.

14,000 gal, goldfish, no Koi. I'd bet serious cash you don't need any external biofilter at all unless you're planning on dumping say 500 or more goldfish in on day one. Your pond will handle it fine. I know it's sacrilege to say such a thing here but biofiltering has to do with fish load and how much food is being fed. Food is converted to waste (ammonia) which is what the biofilters convert.

calculating the size of the skippy filters based on turn over and pond size

That makes no sense to me. Fish load, the only reason for a biofilter, isn't part of the equation. Also I don't think there's ever been any kind of data on how large a fish load a skippy could handle. And then you have an endless choice of media most of which is also untested. So I think your guess would be as good as anyone.

You can tell exactly how much biofilter to add by measuring ammonia levels. Zero level means no need for biofilters. Seems to me a common sense approach is to add the fish, test ammonia (which should always be done anyways) and then add biofiltering as needed.

I've heard lots of new pond owners say "well I just want to be safe" but that's a false sense of security. Even if you build a skippy, or 2, or 10, you still need to test ammonia to know whether you need more. Don't get me wrong, I think it's fine, doesn't hurt anything, to add as many skippys as you like. But if you're asking "do I need to go to this expense and trouble" the answer is probably no and testing ammonia is the only way to tell.

This whole biofilter thing came from Koi ponds. And by Koi pond I don't mean a pond with some Koi. I mean a pond full of large Koi. Those ponds get more food in one day than most water gardens (goldfish and a few Koi) see in a month or even a year. They may be stocked with 200 lbs of large, and expensive, Koi on day one. They actually need the biofilters. They need to be fully cycled on day one. And BTW, they don't use skippys. Their common DIY choice is trickle tower.

If you wanted to invest time and money into something I think you'd get more out of a stream or bog. In addition to being biofilters they have a better chance of killing green water algae. They're a better choice, imo, for growing different kind of good bacteria instead of just ammonia converters.

 

[Andy41]

Hi Waterbug,

You make some interesting points here.

The pond will be stocked with about 10 goldfish to start with, but they breed like hell, and i know from my previous pond that this causes issues with ammonia etc. I added a skippy to that pond to cure that.

This pond is 6x the size of the old one though, which dilutes everything, until the fish breed so much that they fill the pond again. Or i stop them before they breed so much. somehow

The stream / bog killing the green algae is an interesting point though, and this is what i'm really interested in. A more natural solution is always better. But the question is to what degree can they clean the water? I'd be interested to hear from anyone with a bog / waterfall about this.... do any of those people also use skippys?

Maybe this will just be trial and error after all. Which brings us back to the question of whether or not the filtration investment is worth it! Confusing

I'll go back and look at the skippy equation again....

cheers,

Andy.

 

[addy1]

Andy,
My pond, around 11k gallons, is only filtered by a bog, no skippy, no uv just the bog. My previous ponds have only been filtered by a bog. Well except the very first one.
The current bog is large, but I wanted the extra plant room. I have a bundle of goldfish and shubunkins, most from fry this year, 100 plus. I have no algae issues, no green water, crystal clear unless I muck it up like I just did grooming the plants. It took about an hour to clear back up, I really mucked it up.........could not even see a fish in the water lol.

My stream also has plantings so it too is like a plant filter.

Water test have been perfect, the only issue I have had is ph, but my well is acidic, once the plants got going the ph leveled out at a nice 7.6 or so.

So needless to say I love my bog.

 

[taherrmann4]

Andy,
My pond has a 15' long creek with about 5 waterfalls ranging in varying heights. My other creek is 8' long that I use more of a plant filter and then my last creek is about 25' long. The waterfalls have the savio filter falls and the large creek has the laguna filter on it. My pond is about 3,000 gallons and I have crystal clear water, I get algae in the creeks and falls that I have to clean out about once a week in the spring when I first start up otherwise I could read the year on a penny if it was in the bottom of my pond and it is 2-3.5' deep. The filters I have work but they were expensive and I could have done it and saved quite a bit of money had I found this forum sooner :sad: . But that is what the next time will be. Don't under estimate the power of the plants as well.

If I was doing it over again I would add a large bog if the area I was putting the pond allowed it if not then I would do a skippy or doc bio filter since they seem to work from quite a few people on here having great success with them and they are quite easy to build and cheap!

 

[addy1]

Neat tmann, my stream is around 85 feet long with 4 bio filter ponds (switch backs coming down the slope), they didn't start out to be bio filters, but the plants grew great and filled them in, so I left them be. I am sure a lot of muck has settled in them, but I am leaving it until spring to clean out, in case frogs have made it their winter home.

I didn't really have an issue with algae this spring, but also had a empty pond except for 4 fish.

 

[koiguy1969]

a dedicated koi pond is different than a garden pond with fish in the fact that it is filtered but has no plants. (i have one of each) therefore requires more maintainence in the form of water changes or a constant influx of fresh water. because of the lack of plants theres nothing to use the nitrates up so they can quickly build up in the water. theres also a neccessity for water changes to dilute pheromones which can build up to the point of shutting down kois immune systems. a skippy style or upflow filter can definately help in any pond system, and are quite effective..but the final product of any bio filter whether its built or bought is nitrates.and pond owners want clear water to enjoy their fish. so a koi ponds owner runs U.V clarifiers to keep down the green water because there arent any plants to use the nitrates. the more fish you cram into the system the more neccessary the water changes become and the more frequent. a koi pond is just that a pond with koi,.. where the fish are the showcased, with a garden pond the pond is the spotighted and the fish are an accent....as far as a skippy filter goes..i keep 200+ inches of fish (all koi) in my 1200 gal pond outdoors and the same in my 800 gal pond in the basement. mine is a 70 gal skippy style. not exactly a true skippy, but their basic design. and i guarantee this wouldnt be posible without the filter,with the 2 or more daily feedings.

 

[sissy]

I have koi and goldfish and have 2 down filters both with lava rock and I have plants and have yet to have any issue's with my pond and my koi are now over 8 years old and I have not lost one fish even with the destruction of my liner this summer by a neighbors dog .I did have 1 fish jump out in the spring and that was a shubby and my water has tested fine and my fish seem healthy enough and seem happy .I do take and net gunk from the bottom 2 or 3 times a week and check my pumps for build up of gunk .Never had a uv so don't know much about them and my water is clear and has yet to turn green .My pond is in full sun but I did make a shade sail for over it this summer and made the the screen cover to keep any more fish from jumping out .

 

[Waterbug]

Andy

This pond is 6x the size of the old one though, which dilutes everything,

I think I know what you mean, but to be precise it's not so much dilution that's the benefit since that would only delay problems for a couple of days if ammonia was building. You have 6x the area for growing nitrifying bacteria.

The only 100% guarantee for killing green water algae is a proper UV filter. You could still have other issues that make water unclear.

Heterotroph Bacteria
Streams and bogs are never a 100% guarantee of clear water because they're a natural system. In these systems you're trying to grow heterotroph bacteria which produce a chemical to bust the algae cell wall so the bacteria can eat the creamy center. Streams and bogs force single algae into close proximity with heterotroph bacteria so they can do their thing.

Streams have the benefit of adding O2 helping the bacteria and exposing the algae to more UV from the sun which can hurt it, causing to to clump together (colonies) for protection. Clumped algae makes the water less green even though there's the same number of cells. Bogs have the benefit of trapping algae and keeping it in the dark for what can be very long periods. Bogs also have the benefit of being able to trap tiny suspended flecks of organic matter which make a pond unclear in ponds older than a couple of years.

Added altogether streams and bogs are not happy places for single cell algae. Best of all, to function properly they need no maintenance for years. And bogs in particular may benefit from clogging silt and organics because that makes a finer matrix trapping algae clumps (single cells are probably still too small). This theory is based on what I saw under the microscope when looking at how fabric filters work.

War on other fronts
However, the single algae may have its own defenses, allelochemicals, which may attack the heterotroph bacteria.

I believe string algae also produce allelochemicals to kill single cell and visa versa as they compete for the same resources. Although the single algae main defense against string algae may be blocking light. Often string algae is added to a pond with plants and the plants get the credit for clearing the water by starving the algea. But a simple water test will always show there are still high levels of all nutrients single algae need.

So the natural process is a war of plant vs bacteria and plant vs plant. Therefore the outcome is always an issue. The nitrifying bacteria have the benefit of not having enemies, their food, ammonia, can't fight back. So they're much easier to grow.

There are many studies that found these general features of bacteria and plants but none that I know of that were done in a backyard pond or clearing water. So everything I said is theory. However I think these theories are better than the seat of the pants, no data at all, theories some other things done in ponds to get clear water.

In cases of ponds with streams, bogs and man made filters the credit will almost always be given to, or at least shared with, the man made filter. That's human nature, not science. Just as taking a poll doesn't tell you anything other than what people feel is going on.

 

[addy1]

Andy
I really did muck up my pond when pulling out the plants it is unreal how much junk is collected in the roots of the plants. I still have more to pull out we are getting cold this weekend so finishing today or tomorrow I hope.

Here is a picture of while I was working on it, you can barely see the fish

This shot is about 2 hours later. I do not have koi, but do have a ton of goldfish and shubunkins
The green you can see behind the fish is the pond wall about 20 feet away.

The best thing you can do, is read, decide what will work for you and do it. You can have a bog and a filter or a filter only or a bog only. My bog is large. There is a ratio of bog to pond in the construction thread bog building.

I chose bog only but I have the room for a large bog, wanted a large one for the plants it could grow. If you do a filter and a bog, just make sure you don't send the filtered water to the bog, the plants need the unfiltered water.

 

[Andy41]

Thanks to everyone who's commented.

I've read through everything here, gone back and recalculated and revised some of my assumptions and earlier mistakes, and i've got a much more realsitic plan now for the filter system.

Special thanks to Addy

cheers,

Andy.

 

[addy1]

Great, keep going forward.