Hi,

New to the forum and koi . I purchased a new home about a year and a half ago and it came with 3 koi ponds. I have closed 2 of the 3 and only have the big 25kl pond left.

My problem is as follows. Everything was home made stuff which seemed to work well other than the sand filter that needed almost daily cleaning. I recently sprung a leak and had to empty the pond. I proceded to dismantle everything in a bid to start over. I chucked everything except the pump which is a .75kw speck porpoise pump, a 3 bag sandfilter with koi media in it (3-5mm) and a 55w uv light. The pond currently has a 110mm bottom drain with a 50mm pipe to the pump.

I have drawn up a diagram of what i think the ideal changes would be.

Please advise on what i need to buy the get the system running effectively as i have had many suggestions from retailers with varying costs and outcomes.

Hi Clivek

Have you managed to locate the leak or leaks?

Hi Clive

Where about are you from?

It can be very simple and relatively cheap to setup good filtration.
If you are cleaning your sand filter every 2nd day then you more than likely have the wrong sand inside. Also modifying the fingers inside and changing to koi sand will help a lot.

Then keep the uv light and just add a bakkie shower for bio filtration and you are good to go.

How many fish do you have, in a 25kl pond I would keep 15 fish max....interested to hear as overcrowind could be adding to you having to clean filters so often if you already have the correct sand in there.

Welcome to the forum, a wealth worth of information here, you will enjoy it here!

I have located the leaks and resealed the whole pond with hydro seal.

There used to be about 50 fish in the pond that ranged from 15cm to about 55cm. There was goldfish and koi and i am sure a few other breeds aswell.

There is no fish at the moment.

I baught the last sand at loolilocks and it said it was 3-5cm koi sand.

I am located in Boksburg.

Will a prefilter help with the filtration of particles before the sand filter? less frequest backwash and clean.

What biofilter do i buy? and what do i put inside? Do i use a venturi and where do i install it.

I intend to suck directly from the bottom drain 80% and 20% from the standoff box / skimmer / weir.

Will this be ok? I have some money to throw after this "problem" but i do not want to waste it on things that make no difference.

clivek wrote:

Will a prefilter help with the filtration of particles before the sand filter? less frequest backwash and clean.

What biofilter do i buy? and what do i put inside? Do i use a venturi and where do i install it.

I intend to suck directly from the bottom drain 80% and 20% from the standoff box / skimmer / weir.

Will this be ok? I have some money to throw after this "problem" but i do not want to waste it on things that make no difference.

I use a Matala pre filter in my settlement chamber as well as some sheets between bottom drains / skimmer and pre filter piping leading to my pump. Is it making a huge difference in my case. I had more than 30 koi in my 30kL pond but got rid of some. With my lower stocking density I have a crystal clear pond and much less rubbish in the water. Like Chris N say - - when a fish double in length they are 8 times heavier, eat 8 times more, produce 8 times more waste and filter must work 8 times more. With 10 fish in pond double the original size this problem becomes huge

As Cliff says, add a bakki on the line where the UV is...and use ultra Zap 25 liter filter...
If U add a prefilter...U will still need to clean it...The idea is to leave the dirt as shorter time as possible in the pond.
Invest in a blower or compressor for the sand filter..it takes 4 min to clean it and less water...by pressing few buttons...Sand filter is never cleaned by back washing...U will need to open it and steer with hand...and it will still not be clean.
Bakki U can make yourself and it will not cost U much.

I think 50l ultra zap will be better.

Thank you for the replies so far,

How do you make a baki filter without it looking "Backyard" and i also need to hide it as all the equipment is hidden behind the waterfall at the moment.

Put it with the rest of the filter equipment and put a collection tray under it with a pipe to discharge at the water fall, by gravity. MANY PEOPLE HAVE THEM IN OPEN VIEW AND IF DONE NEATLY is not too bad.

Time to research Bakki filters.

Hi Clive, I have all the above options on my pond currently.

You are welcome to come past for a visit and to get some ideas?

I stay near Greenstone mall, near edenvale.

Let me know and we can chat about all options.

Bakkie shower can be easily hid and does not have to be next to the pond.

Look under Trickle filters as well , Same thing.

Hi - A few suggestions.

I see you want to refine the system you have rather than dynamite everything out and spend a lot of money on a completely different system. That’s great because you do not need to do much.

The bottom drain to the pump is 50mm - not ideal but it will do. You mentioned sucking from a skimmer or weir but that is not on the diagram. So you have two inlets to the pump - how are these plumbed together (important point this).

The pre-filter with brushes after the pump - is this a bought unit or did you build a system? If it is a bought unit (the tube with a brush in it) then I suggest you move it to before the pump. You would therefore suck through the unit rather than push the water through it. There is a lot of pressure between the pump and the sand filter. This unit will last much longer on the suction side. It is a good idea to try to remove some of the solid before the pump on a suction system.

Then if it is a bought unit and you have a second suction line from the weir then I would add a second pre-filter to this line before the pump. You would now have double the pre-filtration before the pump. Remember these units need constant flushing to get the trapped solid out of the system.

In all cases of re-doing any piping avoid 90 degree bends like the plague. Especially if you have 50mm piping already. Every 90 degree bend add about 500mm of head to the pump – i.e. if you have 10 90 degree bends on your system it’s the same as pumping the water vertically for 5 meters – you get less water out the other side.

The speck pump is a great pump.

On the other side of the pump you concern seems to be the sand filter blocking. What type of sand filter is it? Have you made any modifications to the arms at the bottom? Do you maintain this regularly? All filters on the push side of pumps tend to block because of the build-up of solids and the pressure. So you can easily get a crust forming in the sand bed over time. I also saw a solid lump of plastic media twice the size of my fist in a bubble bead filter a few months ago. This had blocked the outlet because this bubble bead filter was never backwashed.

Sand filters are very efficient and you will get clear water. You will also have a fair amount of biological action inside the sand bed. I know of people who have nothing but sand filters on their ponds. Their fish are alive and healthy for many years. I too have run a pond on nothing but sand filters about 30 years ago. So while everyone is trying to sell you something new and expensive there is nothing wrong with them.

You might consider a second sand filter - in parallel - this would have the effect of slowing the water down as it passes through two sand beds and the overall flow rate will be increased because you will largely eliminate the severe restrictions one sand filter places on the pump flow rate. In this way you will get a faster turnover rate and the solids in the pond will be removed at a faster rate.

If the sand filters are correctly set up and regularly maintained they will work.

You have a 25L biofilter on the system at the moment. If you want to increase the biofilter capacity a trickle tower/ bakki shower is a very good option. You can buy one or you can build one.

As for venturies - yes but depending on the make. You could also increase the oxygen content of the pond water by building a larger waterfall or even a stream leading to the pond. Both of these have aesthetic appeal in the garden rather than a venturi sucking away.

Chris

Q: The bottom drain to the pump is 50mm - not ideal but it will do. You mentioned sucking from a skimmer or weir but that is not on the diagram. So you have two inlets to the pump - how are these plumbed together (important point this).

A: It is not plumbed at the moment. I was thinking of puting a T in the primary line with a ball valve to regulate the flow.

Q: The pre-filter with brushes after the pump - is this a bought unit or did you build a system?

A: Its a bought system.

Q: What type of sand filter is it? Have you made any modifications to the arms at the bottom?

A: It is a koi sandfilter (2 bag i found out today) No mods.

Q:Do you maintain this regularly?

A: yes every second say about. Thats why i am also redoing it.

The venturi's are there to circulate the water as primary function and secondly add oxygen.


I have been quoted 9k to recomission the system today.

clivek wrote:

Q: The bottom drain to the pump is 50mm - not ideal but it will do. You mentioned sucking from a skimmer or weir but that is not on the diagram. So you have two inlets to the pump - how are these plumbed together (important point this).

A: It is not plumbed at the moment. I was thinking of puting a T in the primary line with a ball valve to regulate the flow.
I did the same, but to reduce friction I used Y
Q: The pre-filter with brushes after the pump - is this a bought unit or did you build a system?

A: Its a bought system.

Q: What type of sand filter is it? Have you made any modifications to the arms at the bottom?

A: It is a koi sandfilter (2 bag i found out today) No mods.

Q:Do you maintain this regularly?

A: yes every second say about. Thats why i am also redoing it.

The venturi's are there to circulate the water as primary function and secondly add oxygen.


I have been quoted 9k to recomission the system today.

U can do it for much less.

Hi -

A 2 bag sand filter on a ,75Kw pump is not a good idea. It is too small and will clog very quickly and a lot of fine stuff will blast through the sand bed. You will have to use something else or use another 3 bag sand filter in parallel to this small filter. I am sure there is a lot of pressure being generated in this small unit. This is the main reason why you have to back wash so often. If you get the sizing right with the sand filter or filters your problems will be over.

The quote for R9000 - what was going to be done for this price?

Diagram of suction onto pump from bottom drain and skimmer. Try not to use a normal T into one 50mm pipe. Water is a strange thing and you will get more suction form the straight part than from the section coming in from the side. This is a more balance and effective way to increase flow rates.

Ok - so how do I load an image? Not sure what is going on here ....

Chris

1 x Speck 3 Bag Sand Filter R2 690.00

3 x Bags Sand R225.00

1 x 25 Liter Bio Filter R850.00

1 x 25 Liter Bio balls R600.00

1 x Pre Filter R975.00

2 x 50mm Venturi R290.00

Pipe, Fittings, ball valves, consumables, etc R1 940.50

Installation R1 424.50

clivek wrote:

1 x Speck 3 Bag Sand Filter R2 690.00

3 x Bags Sand R225.00

1 x 25 Liter Bio Filter R850.00

1 x 25 Liter Bio balls R600.00

1 x Pre Filter R975.00

2 x 50mm Venturi R290.00

Pipe, Fittings, ball valves, consumables, etc R1 940.50

Installation R1 424.50

I think U can find the sand filter even cheaper...Ask Nev...he removed his old sand filter...Just need to buy the manifold...or he can get u cheaper sand filter...(I think)
What bio filter and prefilter u plan to buy? Make? Name?...

The more i look into this the more i find that my equipment is inadequate.

The pump which i thaught was a 0.75kw is actually a 0.45kw pump. Porpoise 90/10

What size pump should i be running? do you get low energy pumps?

Do not despair...two smaller pumps is better than one big one...in case one packs up U have back up.
Yes there are low energy pumps like PC18000, and the ecotouch, which U can run on low for normal operations and put on high for backwashing.

Hi -

Put the brakes on please.

A Speck Porpoise 10 will give you about 15,000L per hour if there are no restrictions. You have a 25,000L pond. So your pump capacity is fine for your pond volume. And you are only using about ,45Kw per hour. Don't spend more on another pump.

You just need to eliminate the frictional losses and restrictions as much as you can.

The low energy pumps are fine but they cannot create much pressure - so they can only lift water up 50cm or so. They cannot push the water through a pressurized system as you have. Therefore to use a low energy pump you will spend much more money converting your system into a gravity fed system. The immediate problem you have is the 50mm bottom drain. You cannot feed enough water to a low energy / high volume pump through 50mm.

I suggest the pump is great for your pond. In the last 20 years pond builders have done a great dis-service to koi keepers - they have build poorly designed filtration systems and then simply put 1.1kW pumps on them to overcome the restrictions. A sort of brute force and ignorance approach. But in today's world a 1,1Kw pump will use about R1000.00 per month on electricity. The ,45Kw Speck will use less than half of that and still work well.

There are variable speed pumps on the market which can vary the speed and volume of the pump between ,3kW - ,5kW and ,75kW. Excellent pumps and well worth thinking about as you can run on the lowest setting and volume through the winter and for some hours during the day in summer saving thousands of rands..

With a waterfall you can eliminate the venturies. Another sand filter (new or second hand) would help. Then a second biofilter - or you can make your own. UV's become not necessary after a few years as your pond matures.

Use the piping - suction > pump > sand filter (sand filters) > biofilters or biotubes > back to pond. Don't split the returns between the UV and the biofilter.

So - the heart of the system the pump is fine.

Chris

Summary

1) Keep the pump as is.

2) Replace 2 bag filter with 3 bag filter

3) use 45 degree bends and no 90's

4) shortest distance from pond back to pond

5) Suction from Bottom Drain > pump 0.45kw > sand filter (new 3 bag) > sand filter (existing 2 bag) > UV here? > Biofilters or biotubes > or UV Here? > Baki Filter > back to pond over waterfall ?


Hope this is correct ???

As you are using a ,45kW pump the 50mm bottom drain is not the end of the world. Pumps are generally better at pushing than sucking. Try to get the pump on ground level and not above the level of the water. Any height up to the pumps and the output falls dramatically. Have the pump fairly close to the pond if possible. The filters etc can be further away because of the pushing power of the pump.

Try to conceal these things to make the area look good in the garden.

Pump > 2 sand filters in parallel (not sequence i.e. one ofter the other){most important - I have diagrams for you} > then if you are going to make bakki shower or buy a bakki shower you do not need any bio tubes or bio balls etc. The bakki shower is your biofilter and is much more efficient than the bio-tubes.

The sand filters in parallel are your mechanical filters and the bakki shower the biofilter. That's all you need.

Send me some pics of your set up and surrounding area directly to me and I will look at the placement for you. I don't always look at the forums and you will get a quicker reply this way.

neaves@mweb.co.za

Hope this helps.
Chris

I emailed you the pics.

Please send me the diagrams.