Ek het so 6maande gelede 'n sement dam gebou en dit uitgeverf met 'damseal'. Moes egter al die water so 3 maande later uittap om lekplek reg te maak.
Die dam is 6m x 3m x 1.6m diep en ek het 4 chambers wat bo die grond gebou is (elkeen 1000l) Het 2 'bottomdrains' van 110mm elke wat met 'n elkel pyp na die 'settlement chamber' toe gaan. In settlement chamber het ek 'n 50mm pyp wat na 'n .75kW motor toe gaan wat water via 7 jets terugplaas na die dam toe. Dit is ongeveer 40cm onder die watervlak. 'n tweede .75kW motor suig ook water uit die 'settlement chamber' via 'n 75mm pyp. Al die water loop dan direk in die 'chambers' in. Tans gebruik ek 120m x 3m skadunet in die 4 'chambers' as filter materiaal.
Die water vloei terug via 'n waterval. Gedeelte van die water vloei in 'n kleiner dam (+-1000L) waarin ek plante het. Die klein dam vloei ook terug in die groot dam via 'n waterval. My dam het ook 'skimmer' wat direk in 'settlement chamber' invloei.
Al my lesings is goed,behalwe die pH wat so 8.5 is. Geen visse het nog gevrek nie en hulle eet asof kos uit die mode gaan en groei goed.
Ek het so 25 visse in dam waarvan so 10 bo 30cm is en die grootste 1 omtrent 60cm.Daar is geen plante in dam nie,net 'n houtbrug.
Dit wil voorkom of die skadunette nie baie goed werk nie want my water bly altyd vuil en sigbaarheid is omtrent 50cm.
Ek werk ongelukkig in Tanzania en is hier vir 3maande op 'n slag en net 2weke tuis. Intussen het ek 28 Matala sheets gekoop en sal my filter aanpas vir 'up-flow' sodra ek weer by huis is. Het ook 'pre-filter' (Ezbio90) gekoop wat ek aan die motor wat die jets voer wil koppel. Ek gebruik ook 'n lugpomp met 6 groot 'air stones'. 4 in filters en 2 in dam. Die pomp lewer 650L/min lug en verbruik 540 watt krag.

Is daar dalk iemand wat my raad kan gee hoe om water kristal helder te kry? Sal die Matala sheets voldoende wees. Dit het oppervlakte van 290 vierkante meter. Is die 30000L per uur watervloei te sterk vir die filter?

Sal met graagte fotos oplaai indien nodig

Hi Marius

Ek merk dat jy nie 'n sandfilter het in jou stelsel nie. Ek glo nog aan sandfilters om daai klein partikel te filtreer. Jy kan oorweeg om dit te voeg, maar gee jou stelsel kans. Dit is 'n nuwe dam en jou probleem sal waarskynlik met tyd en (maturity) opgelos word.

Het jy behoorlike UV filters? 'n Dam sonder UV filters sal altyd 'n alge probleem he, veral in die eerste jaar. Dit is waarskynlik die vryvloeiende alge wat jou sigbaarheid beperk. Dit klink of jy 'n indrukwekende stelsel het, en my advies is om nie sonder ten minste twee 50 watt UV's te opereer nie.

'n Ander moontlike probleem is dat jou vloei deur jou filters (deur die skadunet) te hoog is. Die water moet baie stadig deur die filters gaan, anders trek die vloei al die vuiligheid saam en terug na jou dam toe.

Skadunet werk redelik goed, maar ek sou dit aanvul met haarkrullers, filter borsels of bioballs. Jy het die spasie in jou filters. Die motala mat blok vinnig op en ek glo nie daaraan nie.

Sal graag fotos wou sien. Dan kan lede baie beter adviseer.

Dankie Paul

Ek sukkel tans om fotos deur photobucket op te laai,maar sal aanhou probeer.
Ek het sommer al teen die 2e dag groenwater gehad maar nadat ek die water die 2de keer in getap het, het alge nie weer terug gekom nie. Ek is baie gelukkig want die dam is in volle son die hele dag lank.
Persoonlik dink ek dat die watervloei te sterk is vir die skadunet aangesien my'chambers' se koppelings almal aan die bo kant van die filters is. Die vuilgoed kry nie kans om af te sak nie en is geneig om bo oor die skadunette te vloei, direk in volgende 'chamber' in.
Sal ook UV's moet insit aangesien ek dit tans glad nie het nie.
Die sandfilter is dalk die beste opsie.Het so 3 jaar gelede 'n 4000L dam gebou en 'n jaar later 'n sandfilter ingesit met uitstekende resultate. Soos die meeste van ons maar fout maak, was my eerste dam te klein n baie vlak. Sal dit in die toekoms as hospitaal dam of teeldam gebruik
Dankie vir 'n goeie webblad oor Koi en ek sal dit sekerlik baie besoek. Net jammer dat ek reeds R30 000 spandeer het op al die Matala sheets terwyl daar goedkoper en beter opsies beskikbaar is. So leer mens maar op die harde manier

Hi -

A very important consideration - in order to retain your flow rates you must use 1 x P30 sand filter for evey 10,000 litres.

These must be plumbed in parrallel.

That is why one sand filter on your small pond worked well. Using one sand filter on 30,000 won't work properly. You will restict you flow rates too much.

Regards,
Chris

Hi Chris

Thanks for the info. Perhaps you can inform me if I will need more that one pump to feed the 3 filters, or can I use my existing pump via the filters before it reaches the 4 chambers.

Any comment about the Matala sheets since I all ready brought them. The sheets are 1.2m x 1m by 40mm thick. I plan to cut them in 1m x .4m strips and stand them vertical in the chambers. Going to use 28 full size sheets with different density. Will modify my chambers to use it as an up flow system. Currently all outlets to the next chamber are at the top via 2 x 110mm pipes.
The pond is in Bloemfontein so I should be able to find the P-30 there.

Regards
Marius

Hi,
What size pump are you running.
Chris

sand filters in parallel

750 Watts (.75kW) and they claim 30000L/hour on the filter chamber. I also have the same size pump sucking water from the settlement chamber and returning water directly via 7 jets to the pond. I also have a huge airpump supplying each filter chamber with air as well as 2 airstones in the pond. Really works well and the water at the surface raises about 20cm from the bubbles created by pump.
Power is costing me a fortune since I have a third 750Watt pump on my 4000L pond.(my first pond dating back to 2007)
They told me it is easy to clean the Matala when installed vertically. Hope this is the case since I am stucked with it. Surface area is 290 Square meters and with the 3 x P30 filled with gravel it should be okay. I filled the 2 waterfalls with white rocks. The stuff people put in the garden or on walkways.
I do have a lot of water movement with the 7 jets and the return via the filter system. I feed good quality food. Hikari and Ichiban that I Buy in Gangster Paradise. I also add clay weekly(if my girlfriend remember, haha)
The pond is in full sun all day long and no plants in main pond but I have a small (+-1000L) pond between the 4 chambers (6m long) and the main pond. Some of the water from main waterfall returns to this small pond and when back to main pond again

Regards
Marius

Hi Marius,
I would need to see some pictures of your pond it get a more accurate idea of what is happening.

I doubt is the ,75Kw pump is giving you 30,000 L per hour – more likely around 22,000 – 24,000 L/h. A 1,1Kw will give you closer to that. Also this varies from pump to pump - depending on the make.

Switch off the second pump from the discharge box returning to the air jets. You have enough air with the water fall and the air blower. That will reduce your running costs by a fair whack.

Alternatively use the second pump to suck from the discharge box then go through 3 sand filters in parallel to polish the water (remember the 2 - 4mm gravel in place of the fine sand) and return to the pond.

I would like to see the design of your chambers.

I see you are in Tanzania?

Regards,
Chris

Hi Marius, if you still have problems upoading your photos, you can E Mail it to me to upload. koi@absamail.co.za

Thanks Paul. Will mail them to you. I did sent it to Chris on his private mail as well, but will forward it to you to.
Very kind of you, and thanks again.

Regards
Marius

Herewith the photos. I made it smaller.

Sand filters in parallel ... truth is that due to simple physics you will never get the total flow fully balanced over the units in the line. It may look impressive.

The slightest density variances in the various filters will immediately reduce flow to the one that offers the most resistance and this will cascade down to the one with the least resistance. That will increase load on the lowest one that will in turn clog up and recycle the distribution to the next "lowest" one and this routine will always be in motion.

In my mind the only real advantage of such a system will be in the sort of automatic loadshedding that happens in the system and as such ensures that you have dynamic "fallback" when maintenance should be neglected.

You will always run into issues on backwashing too unless you can close off the incoming water in each filter individually.

Hi Colyn,

The purpose of placing sand filter in parallel is to maintain flow rates. It is not the least important that there may be some slight variance or balance between the chambers.

Back washing sand filters has ALWAYS to be done with all sand filters closed except one. You back wash one at a time or the sand filters will not flush correctly. The outlet pipe from sand filters also has to be of reasonable diameter or the sand filters will not back-flush correctly. The back-washing of sand filters is actually related to the size of the pump. A 18 inch sand filter can have a ,6Kw pump. A 24 inch sand filter can have a ,75KW and a 30 inch sand filer can have a 1,1kw. But a ,6Kw pump will not work on a 30 inch sand filter. It is not powerful enough to lift and break up the sand bed. This can be over come to a large extent by opening the filter and stirring the sand bed whilst the pump is back washing the filter.

Sand filters are not perfect but if you are going to use them then you have to use them in certain ways to get them to work on koi ponds.

We know that the size sand has to be changed. The fine sand from swimming pools simply works so well at removing solids it clogs every few days. So a larger size sand granule is used and this works well.

A basic principal for koi ponds is to try to get the volume of the pond through the filter system in 2 hours or less. There are many variables to this but that is a general rule.

It makes no sense to have a sophisticated filtration system then pump the water through a single sand filter. The sand bed is restrictive of flow rates; the multi port valve is restrictive of flow rates. You need to turn the water over as quickly as possible for various reasons.

Many filters used on koi ponds have design faults. This is quite an interesting subject in its self. We need to be aware of certain basics to get these things to work properly.

Take the vortex chamber for example. These are usually placed on ground level and gravity fed with the pump sucking at the far end. The flow rate is determined by the diameter of the pipes linking each chamber. If you have a pump with a larger capacity than the flow rates through the pipes then the chambers will suck dry. To overcome this some designers of ponds restrict the flow to the pump. Further, in order to clean ANY filter properly you have to be able to drain the chamber and rinse it down.

In a vortex system, for example, how do you drain the tank? You cannot. AND many systems are installed without any means of isolating each chamber. The end result is organics building up over time and polluting the water. So many vortex systems have been removed from ponds because of this.

All prefabricated filter systems have a limit as to the amount of water that can be moved through them. Manufacturers and sellers of these filters should tell you - this filter has a capacity of x litres per hour.

If you are going to use prefabricated filters on your pond and you need more than one what do you do - you place them in parallel. The end result is the same as building a filter chamber with a larger horizontal cross section. Same with sand filters when you use them. As a general rule one 30 inch sand filter per 10,000 litres. This is to get the pond volume through this apparatus in under two hours. Because of the restrictions, as the pond volume increases you have to increase the volume of water going through the sand filters and the only way you can do this is to place several in parallel.

Thanks for raising this subject Colyn - it is fascinating. I am always willing to learn new ideas that work. Keep them coming.

Chris

Thanks for all the interesting replies. Every comment makes sense, what's why the hobby is so interesting since many methods will work. But why can't anyone give me an answer about the Matala sheets since I am stucked with it and my time is limited to install them. I work in Tanzania and only have 12 days every 3 months to attend to my pond so I want to make the most of if when I am home in a week's time.
I might not have the perfect setup as I am new to large ponds. Fishies seem to be happy so far but as we all know this can be for the worse in a short time. Might not see them when they down under,but they eat like crazy and grow like mad.
My first small pond had the usual problems as expected from a new pond but I was convinced that the second pond will work well from the start. I know that all ponds will have problems at first, so I might be naive and have little patients. Maybe it is because I am not home often and I also know that my setup is far from perfect as a novice.
I am prepared to spend more money on my setup but in the shortest amount of time. So many things to do at home beside the pond
I love my hobby but cant spend time rebuiding everything.
Will the matala work if I install it in a proper way? I can add a sandfilter on my 7 x return jets, but to install the filter at the end of my chamber-chain means I have to add another pump. Then I will have 4 x 750watt pumps (including my small pond) and a huge airpump. Including the lights this will be close to 4kWatts or 4000watts of power drawn 24/7 x 365.25days a year, providing Eskom plays along.
Come on guys, you have good experience in this great hobby. Any ideas?? Good or bad will do.
Thanks for a great forum, this is what it's all about

Hi Marius,

Can you give us a description on how the water flows through your filter chambers and how you intend to clean the filter chambers please. Also how is the media packed? And which way does the water flow inside the chambers.

Different media can be discussed.

I would certainly not use the one pump to create such vigorous circulation. Your koi will end up looking like eels.

As Colyn said koi are carp and are used to still waters rather than other fish which enjoy swimming upstream.

However, you still need some gentle circulation of the water in the pond. This will distribute the oxygen coming in from the waterfalls and also distribute the impurities such as ammonia more evenly throughout the water.

With ideas you should be able to run the entire system on one pump or possibly two.

Regards,
Chris

Hi Chris

Currently all water exits to the following chamber goes via 2 x 110mm pipes, fitted at the top of the filter. With the Matala I am going to built a plastic 'compartment' inside each chamber that will start off about 300mm from the bottom, reaching to the top of the chamber. This way the water will enter at the bottom of the sheets creating an up flow system.The sheets will cover more or less half of the chamber. Going to slide the sheets in vertically and going to use a combination of different densities of sheets in each chamber. I will use 28 full size sheets by will cut each sheet into 3 pieces. They will be 1m wide, 40cm high and 4cm thick. Will end up having 72 sheets fitted vertically and 4 coarse sheets as supports at the bottm of each chamber.
At the top of the sheets the water will exit via existing pipes to the next chamber and process starts over. This is the info I gathered from the Matala website.
It is according to then an easy tast to clean the sheets by simply pulling the sheets out, one by one and give it a gentle shake. The blue and grey sheets, with higher density, needs to be cleaned more properly.
By using the upflow system some of the bigger particles should settle at the bottom of each chamber. Will switch of my pump and open the 110mm bottom drains in each chamber one by one, as needed.
I plan to do this mods in about 10days, then I return to SA for my holiday.
I should have planned this pond better from the start. I am sure the Matala will work good but find very liitle info about the flow rates on the internet. I made calculations that the 28 x 1.2m x 1m x .04m sheets will have a surface area of 291 square meters.
My concern is that even with the high density sheets towards my outlet, that some fine particals will still re-enter the pond. That is why I think it will be a good idea to fit sandfilters on the motor returning water to the 7 jets as you suggested.

Regards
Marius

INFO FROM MATALA WEBSITE:

Made of curly fibre Thermo-Polypropylene Compounds that are formed into layers and shapes of different thickness.
Specific Surface: 4 types available, Specific Surface ranging from 200 to 490 m ² /m ³
4 Densities allow for step-wise transition from mechanical to biological filtration.
Excellent surface area with good adhesion of nitrifying bacteria. A high number of interstitial spaces in the tri-dimensional matrix of the filter media improve an early and even growth of bacteria.
Very resistant to plugging. Perfect for pre-filtration and sedimentation chambers.
Excellent 3-dimensional distribution; Even water distribution
High free volume:> 94%
Gradual and efficient capture of particles, when used progressively
Cleaning can be done fast and easy
Form-stable, self-supporting grid type available
Good rigidity
The material is resistant against corrosion, weather, light, temperature fluctuations and chemicals
This filter-media can be cut easily with a kitchen knife, circular saw or band saw and installed in different directions
The material is non-toxic, recyclable , sage to use and very environmental friendly
Light weight, versatile and durable
Relatively transport friendly
The price per specific surface is quite acceptable, given the multiple advantages.
Cleaning of the filters is simplicity itself and the time spent on maintenance is a fraction of that previously expended on the sand filters system. The flushing of the filters is simplicity itself, takes about 30 mins every 4 to 6 weeks, rather than 30 mins every third day !!!!

Furthermore, a good biofilter media requires what is called interstitial spaces. These are the small open spaces in between the media where bacteria can "fill up" in a safe and slimy bacterial matrix. Bacteria love interstitial spaces. The perfect media would let go of the dirt during cleaning but sustain the bacteria attached. He realized that many of these requirements are contradictory to one another. Marc, knew that water will always travel the path of least resistance; so his media would have to be positioned in a filter so the water does not go around it. This would require a somewhat rigid type material in order to be wedged in place. He found that another benefit to being rigid was that the media could be self supporting. Always thinking, he concluded that the material would actually be easier to work with if it had a very slight bouyancy. This way it would not end up at the bottom of the filter tank. After many trials and sleepless nights he came up with a series of 4 filter pads with progressive densities which could be used separately or together to complement one another. He gave them different colors so they would be easy to differentiate. Each pad has it’s own unique structure lending itself to a different job in filtration.
Pour a full bucket of water over specific sections of the filter media

Take out 2 sheets of Matala and shake the remaining sheets up and down in the filter tank; drain the chamber.

Remove the media from the tank; dirty water falls off; drain chamber.

Important Notes:

Remove media only if strictly necessary; The above picture proves Matala release its dirt quit easy.
DO NOT THROW MATALA ON THE GROUND TO KNOCK LOOSE DIRT.
Over zealous cleaning is not necessary and will lose too much bacteria. Keep it gentle.
Shake the media up and down in the filter tank; drain chamber

Regards
Marius

Hi Marius,
Another question - I see from the photos that each chamber is linked by two 110 mm pipes at the top of each chamber. How do you get the water to flow through the media? Are there pipes at the bottom of each chamber? If so how will the water flow to the bottom if there are pipes at the top? i.e. water will take the path of least resistance.

Some notes on media:

Any media will work. Bacteria are remarkable and will grow anywhere. Once they are established they form bio-films and become protected and very resilient.

The nitrifying bacteria that chemically change ammonia to nitrite to nitrate take up a small area on the media. Heterotrophic bacteria take up a large amount of space. Which is why it is always a good idea to make large filters - as you have done.

The way the media is packed in each chamber is critical. Presumable the water is flowing downwards in one chamber then upwards in the next. Always have a chamber at the bottom of the media. 20 - 30 cm or what ever. As water moves upwards through the media the hydraulic load will be even and the water will move evenly through the media.

Media placed on the floor of the chamber will have areas of organics building up.





Make sure the media is packed well - any media. There should be no opening on the side or in the middle. Water takes the path of least resistance and will flow through these opening without passing through the media. The filter will become less efficient.

I suggest if you have these basic things in place that you leave the media in place for cleaning. Open your drains in the chambers and rinse the media down from the top. The sediment and organics will flush into the open space at the bottom (another reason for this open space) and be flushed away without the fine sediment going back to the pond.

Last week I received a phone call from a prominent koi keeper whose water has been pea green for some weeks. As his pond has been going for a few years with clear water we really had to scratch our heads about this one. The only conclusion we could reach was that he cleaned his Matala media thoroughly and disturbed a large proportion of the heterotrophic bacteria. These bacteria are organic munchers.

Regards,
Chris

Thank you Chris for info. I will send you a pm with the drawing since I can not upload photos here.
The drawing will indicate how I will modify the top entry chambers to become an up flow system with the 30cm gap at bottom of media.

Regards
Marius

Hi Marius,
Here is the picture you sent me.



Some questions:

Your diagram does not show me how the water moves from chamber to chamber.

The rest of it looks great.

Remember you can use anything for a media.

Perhaps - as a suggestion - why don't you use the first chamber and even the second chambers as mechanical filters with brushes. This should be cheaper than the matting you want to use. Also a good way to catch the organics. Then you can give them a good blast with the hose to clean them after draining the chambers every now and again.

Using this method you may even get away without sand filters. Actually try this first before spending any money on sand filters. The other two chambers with matting should give you more than enough surface area for nitrifying bacteria to grow on.

Just ensure the chambers can be isolated and can be cleaned easily.

Kind regards,
Chris.

Back in SA now and will start my second job today. Will install the UV's and Exbio90 pre-filter today. Plenty green water which I thought was better but I was wrong. All readingm 0 and pH 8.5.
Will do filters later this week and give feedback. See small leak on my air pump output and will fix that as well.

Is it best to connect UV's in parallel to get slower water flow, or must I connect then in series; longer contact time but also higher flowrate???

I don't think it is going to make a big difference. However, if your flow rate on that line is more than the maximum for your specific UV, do it in parallel.

Marius has send photos of the improvement of his pond after installing 3 x 55 Watt UV's

Day 1



Day 5 - Could see his bottom drain

The joy of a green pond